Find the best tutors and institutes for Class 12 Tuition
Q5.5 (i):
Specify the oxidation numbers of the metals: ([Co(H_{2}O)(CN)(en)_{2}]^{2+})
Solution :
Step 1: Identification of Coordination Sphere Components
To determine the oxidation state of the central metal ion (Cobalt, $\text{Co}$), we must identify the individual charges of all ligands coordinated to the metal within the coordination sphere $[ \text{Co}(\text{H}_2\text{O})(\text{CN})(\text{en})_2 ]^{2+}$.
| Ligand | Number of Ligands | Charge per Ligand |
|---|---|---|
| $\text{H}_2\text{O}$ (Aqua) | 1 | $0$ [Neutral molecule] |
| $\text{CN}^-$ (Cyano) | 1 | $-1$ [Anionic ligand] |
| $\text{en}$ (Ethylenediamine) | 2 | $0$ [Neutral bidentate chelate] |
Step 2: Mathematical Formulation of the Oxidation State
Let the oxidation number of Cobalt be denoted as $x$. According to the algebraic sum rule for coordination complexes, the sum of the oxidation numbers of all atoms in the complex ion must equal the net charge of the coordination entity [Per IUPAC Nomenclature Rules for Coordination Compounds].
The equation is structured as follows:
$x + [1 \times (\text{charge of } \text{H}_2\text{O})] + [1 \times (\text{charge of } \text{CN}^-)] + [2 \times (\text{charge of } \text{en})] = \text{Net Charge}$
Step 3: Algebraic Calculation
Substituting the values derived in Step 1 into the equation:
$x + [1 \times (0)] + [1 \times (-1)] + [2 \times (0)] = +2$
Solving for $x$:
$x + 0 - 1 + 0 = +2$
$x - 1 = +2$
$x = +2 + 1$
$x = +3$
Step 4: Geometric Contextualization
The complex is an octahedral species where Cobalt acts as the central metal atom. The oxidation state $+3$ indicates that Cobalt has lost three electrons to form the complex, typically resulting in a $d^6$ configuration for the $\text{Co}^{3+}$ ion.
Final Solution: The oxidation number of the metal (Cobalt) is $+3$.
More Questions from Class 12 Chemistry Coordination Compounds Exercises
- Q5.1: Explain the bonding in coordination compounds in terms of Wernerโs postulates.
- Q5.1: Explain the bonding in coordination compounds in terms of Wernerโs postulates.
- Q5.10 (i): Draw the structures of optical isomers of: ([Cr(C_{2}O_{4})_{3}]^{3-})
- Q5.10 (ii): Draw the structures of optical isomers of: ([PtCl_{2}(en)_{2}]^{2+})
- Q5.10 (iii): Draw the structures of optical isomers of: ([Cr(NH_{3})_{2}Cl_{2}(en)]^{+})
- Q5.10(i): Draw the structures of optical isomers of: \([Cr(C_{2}O_{4})_{3}]^{3-}\)
- Q5.10(ii): Draw the structures of optical isomers of: \([PtCl_{2}(en)_{2}]^{2+}\)
- Q5.10(iii): Draw the structures of optical isomers of: \([Cr(NH_{3})_{2}Cl_{2}(en)]^{+}\)
- Q5.11 (i): Draw all the isomers (geometrical and optical) of: ([CoCl_{2}(en)_{2}]^{+})
- Q5.11 (ii): Draw all the isomers (geometrical and optical) of: ([Co(NH_{3})Cl(en)_{2}]^{2+})
- Q5.11 (iii): Draw all the isomers (geometrical and optical) of: ([Co(NH_{3})_{2}Cl_{2}(en)]^{+})
- Q5.11(i): Draw all the isomers (geometrical and optical) of: \([CoCl_{2}(en)_{2}]^{+}\)
- Q5.11(ii): Draw all the isomers (geometrical and optical) of: \([Co(NH_{3})Cl(en)_{2}]^{2+}\)
- Q5.11(iii): Draw all the isomers (geometrical and optical) of: \([Co(NH_{3})_{2}Cl_{2}(en)]^{+}\)
- Q5.12: Write all the geometrical isomers of \([Pt(NH_{3})(Br)(Cl)(py)]\) and how many of these will exhibit optical isomers?
- Q5.12: Write all the geometrical isomers of ([Pt(NH_{3})(Br)(Cl)(py)]) and how many of these will exhibit optical isomers?
- Q5.13: Aqueous copper sulphate solution (blue in colour) gives: (i) a green precipitate with aqueous potassium fluoride and (ii) a bright green solution with aqueous potassium chloride. Explain these experimental results.
- Q5.13: Aqueous copper sulphate solution (blue in colour) gives: (i) a green precipitate with aqueous potassium fluoride and (ii) a bright green solution with aqueous potassium chloride. Explain these experimental results.
- Q5.14: What is the coordination entity formed when excess of aqueous \(KCN\) is added to an aqueous solution of copper sulphate? Why is it that no precipitate of copper sulphide is obtained when \(H_{2}S(g)\) is passed through this solution?
- Q5.14: What is the coordination entity formed when excess of aqueous KCN is added to an aqueous solution of copper sulphate? Why is it that no precipitate of copper sulphide is obtained when ((H_{2}S(g))) is passed through this solution?
- Q5.15 (i): Discuss the nature of bonding on the basis of valence bond theory: ([Fe(CN)_{6}]^{4-})
- Q5.15 (ii): Discuss the nature of bonding on the basis of valence bond theory: ([FeF_{6}]^{3-})
- Q5.15 (iii): Discuss the nature of bonding on the basis of valence bond theory: ([Co(C_{2}O_{4})_{3}]^{3-})
- Q5.15 (iv): Discuss the nature of bonding on the basis of valence bond theory: ([CoF_{6}]^{3-})
- Q5.15(i): Discuss the nature of bonding in the following coordination entities on the basis of valence bond theory: \([Fe(CN)_{6}]^{4-}\)
- Q5.15(ii): Discuss the nature of bonding in the following coordination entities on the basis of valence bond theory: \([FeF_{6}]^{3-}\)
- Q5.15(iii): Discuss the nature of bonding in the following coordination entities on the basis of valence bond theory: \([Co(C_{2}O_{4})_{3}]^{3-}\)
- Q5.15(iv): Discuss the nature of bonding in the following coordination entities on the basis of valence bond theory: \([CoF_{6}]^{3-}\)
- Q5.16: Draw figure to show the splitting of d orbitals in an octahedral crystal field.
- Q5.16: Draw figure to show the splitting of d orbitals in an octahedral crystal field.
- Q5.17: What is spectrochemical series? Explain the difference between a weak field ligand and a strong field ligand.
- Q5.17: What is spectrochemical series? Explain the difference between a weak field ligand and a strong field ligand.
- Q5.18: What is crystal field splitting energy? How does the magnitude of \(\Delta_{o}\) decide the actual configuration of d orbitals in a coordination entity?
- Q5.18: What is crystal field splitting energy? How does the magnitude of (\Delta_{o}) decide the actual configuration of d orbitals in a coordination entity?
- Q5.19: \([Cr(NH_{3})_{6}]^{3+}\) is paramagnetic while \([Ni(CN)_{4}]^{2-}\) is diamagnetic. Explain why?
- Q5.19: ([Cr(NH_{3})_{6}]^{3+}) is paramagnetic while ([Ni(CN)_{4}]^{2-}) is diamagnetic. Explain why?
- Q5.2: \(FeSO_{4}\) solution mixed with \((NH_{4})_{2}SO_{4}\) solution in 1:1 molar ratio gives the test of \(Fe^{2+}\) ion but \(CuSO_{4}\) solution mixed with aqueous ammonia in 1:4 molar ratio does not give the test of \(Cu^{2+}\) ion. Explain why?
- Q5.2: ((FeSO_{4})) solution mixed with ((NH_{4})_{2}SO_{4}) solution in 1:1 molar ratio gives the test of ((Fe^{2+})) ion but ((CuSO_{4})) solution mixed with aqueous ammonia in 1:4 molar ratio does not give the test of ((Cu^{2+})) ion. Explain why?
- Q5.20: A solution of \([Ni(H_{2}O)_{6}]^{2+}\) is green but a solution of \([Ni(CN)_{4}]^{2-}\) is colourless. Explain.
- Q5.20: A solution of ([Ni(H_{2}O)_{6}]^{2+}) is green but a solution of ([Ni(CN)_{4}]^{2-}) is colourless. Explain.
- Q5.21: \([Fe(CN)_{6}]^{4-}\) and \([Fe(H_{2}O)_{6}]^{2+}\) are of different colours in dilute solutions. Why?
- Q5.21: ([Fe(CN)_{6}]^{4-}) and ([Fe(H_{2}O)_{6}]^{2+}) are of different colours in dilute solutions. Why?
- Q5.22: Discuss the nature of bonding in metal carbonyls.
- Q5.22: Discuss the nature of bonding in metal carbonyls.
- Q5.23 (i): Give the oxidation state, d orbital occupation and coordination number of the central metal ion: (K_{3}[Co(C_{2}O_{4})_{3}])
- Q5.23 (ii): Give the oxidation state, d orbital occupation and coordination number of the central metal ion: (cis-[CrCl_{2}(en)_{2}]Cl)
- Q5.23 (iii): Give the oxidation state, d orbital occupation and coordination number of the central metal ion: ((NH_{4})_{2}[CoF_{4}])
- Q5.23 (iv): Give the oxidation state, d orbital occupation and coordination number of the central metal ion: ([Mn(H_{2}O)_{6}]SO_{4})
- Q5.23(i): Give the oxidation state, d orbital occupation and coordination number of the central metal ion in the following complexes: \(K_{3}[Co(C_{2}O_{4})_{3}]\)
- Q5.23(ii): Give the oxidation state, d orbital occupation and coordination number of the central metal ion in the following complexes: cis-\([CrCl_{2}(en)_{2}]Cl\)
- Q5.23(iii): Give the oxidation state, d orbital occupation and coordination number of the central metal ion in the following complexes: \((NH_{4})_{2}[CoF_{4}]\)
- Q5.23(iv): Give the oxidation state, d orbital occupation and coordination number of the central metal ion in the following complexes: \([Mn(H_{2}O)_{6}]SO_{4}\)
- Q5.24 (i): Write down the IUPAC name for the complex and indicate the oxidation state, electronic configuration and coordination number. Also give stereochemistry and magnetic moment of the complex: (K[Cr(H_{2}O)_{2}(C_{2}O_{4})_{2}].3H_{2}O)
- Q5.24 (ii): Write down the IUPAC name for the complex and indicate the oxidation state, electronic configuration and coordination number. Also give stereochemistry and magnetic moment of the complex: ([Co(NH_{3})_{5}Cl]Cl_{2})
- Q5.24 (iii): Write down the IUPAC name for the complex and indicate the oxidation state, electronic configuration and coordination number. Also give stereochemistry and magnetic moment of the complex: ([CrCl_{3}(py)_{3}])
- Q5.24 (iv): Write down the IUPAC name for the complex and indicate the oxidation state, electronic configuration and coordination number. Also give stereochemistry and magnetic moment of the complex: (Cs[FeCl_{4}])
- Q5.24 (v): Write down the IUPAC name for the complex and indicate the oxidation state, electronic configuration and coordination number. Also give stereochemistry and magnetic moment of the complex: (K_{4}[Mn(CN)_{6}])
- Q5.24(i): Write down the IUPAC name for each of the following complexes and indicate the oxidation state, electronic configuration and coordination number. Also give stereochemistry and magnetic moment of the complex: \(K[Cr(H_{2}O)_{2}(C_{2}O_{4})_{2}].3H_{2}O\)
- Q5.24(ii): Write down the IUPAC name for each of the following complexes and indicate the oxidation state, electronic configuration and coordination number. Also give stereochemistry and magnetic moment of the complex: \([Co(NH_{3})_{5}Cl]Cl_{2}\)
- Q5.24(iii): Write down the IUPAC name for each of the following complexes and indicate the oxidation state, electronic configuration and coordination number. Also give stereochemistry and magnetic moment of the complex: \([CrCl_{3}(py)_{3}]\)
- Q5.24(iv): Write down the IUPAC name for each of the following complexes and indicate the oxidation state, electronic configuration and coordination number. Also give stereochemistry and magnetic moment of the complex: \(Cs[FeCl_{4}]\)
- Q5.24(v): Write down the IUPAC name for each of the following complexes and indicate the oxidation state, electronic configuration and coordination number. Also give stereochemistry and magnetic moment of the complex: \(K_{4}[Mn(CN)_{6}]\)
- Q5.25: Explain the violet colour of the complex \([Ti(H_{2}O)_{6}]^{3+}\) on the basis of crystal field theory.
- Q5.25: Explain the violet colour of the complex ([Ti(H_{2}O)_{6}]^{3+}) on the basis of crystal field theory.
- Q5.26: What is meant by the chelate effect? Give an example.
- Q5.26: What is meant by the chelate effect? Give an example.
- Q5.27: Discuss briefly giving an example in each case the role of coordination compounds in: (i) biological systems (iii) analytical chemistry (ii) medicinal chemistry and (iv) extraction/metallurgy of metals.
- Q5.27(i): Discuss briefly giving an example in each case the role of coordination compounds in: biological systems
- Q5.27(ii): Discuss briefly giving an example in each case the role of coordination compounds in: medicinal chemistry
- Q5.27(iii): Discuss briefly giving an example in each case the role of coordination compounds in: analytical chemistry
- Q5.27(iv): Discuss briefly giving an example in each case the role of coordination compounds in: extraction/metallurgy of metals.
- Q5.28: How many ions are produced from the complex \(Co(NH_{3})_{6}Cl_{2}\) in solution?
- Q5.28: How many ions are produced from the complex (Co(NH_{3})_{6}Cl_{2}) in solution?
- Q5.29: Amongst the following ions which one has the highest magnetic moment value?
- Q5.29: Amongst the following ions which one has the highest magnetic moment value?
- Q5.3: Explain with two examples each of the following: coordination entity, ligand, coordination number, coordination polyhedron, homoleptic and heteroleptic.
- Q5.3: Explain with two examples each of the following: coordination entity, ligand, coordination number, coordination polyhedron, homoleptic and heteroleptic.
- Q5.30: Amongst the following, the most stable complex is
- Q5.30: Amongst the following, the most stable complex is
- Q5.31: What will be the correct order for the wavelengths of absorption in the visible region for the following: \([Ni(NO_{2})_{6}]^{4-}\), \([Ni(NH_{3})_{6}]^{2+}\), \([Ni(H_{2}O)_{6}]^{2+}\)?
- Q5.31: What will be the correct order for the wavelengths of absorption in the visible region for the following: ([Ni(NO_{2})_{6}]^{4-}), ([Ni(NH_{3})_{6}]^{2+}), ([Ni(H_{2}O)_{6}]^{2+})?
- Q5.4: What is meant by unidentate, didentate and ambidentate ligands? Give two examples for each.
- Q5.4: What is meant by unidentate, didentate and ambidentate ligands? Give two examples for each.
- Q5.5 (ii): Specify the oxidation numbers of the metals: ([CoBr_{2}(en)_{2}]^{+})
- Q5.5 (iii): Specify the oxidation numbers of the metals: ([PtCl_{4}]^{2-})
- Q5.5 (iv): Specify the oxidation numbers of the metals: (K_{3}[Fe(CN)_{6}])
- Q5.5 (v): Specify the oxidation numbers of the metals: ([Cr(NH_{3})_{3}Cl_{3}])
- Q5.5(i): Specify the oxidation numbers of the metals in the following coordination entities: \([Co(H_{2}O)(CN)(en)_{2}]^{2+}\)
- Q5.5(ii): Specify the oxidation numbers of the metals in the following coordination entities: \([CoBr_{2}(en)_{2}]^{+}\)
- Q5.5(iii): Specify the oxidation numbers of the metals in the following coordination entities: \([PtCl_{4}]^{2-}\)
- Q5.5(iv): Specify the oxidation numbers of the metals in the following coordination entities: \(K_{3}[Fe(CN)_{6}]\)
- Q5.5(v): Specify the oxidation numbers of the metals in the following coordination entities: \([Cr(NH_{3})_{3}Cl_{3}]\)
- Q5.6 (i): Using IUPAC norms write the formulas: Tetrahydroxidozincate(II)
- Q5.6 (ii): Using IUPAC norms write the formulas: Potassium tetrachloridopalladate(II)
- Q5.6 (iii): Using IUPAC norms write the formulas: Diamminedichloridoplatinum(II)
- Q5.6 (iv): Using IUPAC norms write the formulas: Potassium tetracyanidonickelate(II)
- Q5.6 (ix): Using IUPAC norms write the formulas: Tetrabromidocuprate(II)
- Q5.6 (v): Using IUPAC norms write the formulas: Pentaamminenitrito-O-cobalt(III)
- Q5.6 (vi): Using IUPAC norms write the formulas: Hexaamminecobalt(III) sulphate
- Q5.6 (vii): Using IUPAC norms write the formulas: Potassium tri(oxalato)chromate(III)
- Q5.6 (viii): Using IUPAC norms write the formulas: Hexaammineplatinum(IV)
- Q5.6 (x): Using IUPAC norms write the formulas: Pentaamminenitrito-N-cobalt(III)
- Q5.6(i): Using IUPAC norms write the formulas for the following: Tetrahydroxidozincate(II)
- Q5.6(ii): Using IUPAC norms write the formulas for the following: Potassium tetrachloridopalladate(II)
- Q5.6(iii): Using IUPAC norms write the formulas for the following: Diamminedichloridoplatinum(II)
- Q5.6(iv): Using IUPAC norms write the formulas for the following: Potassium tetracyanidonickelate(II)
- Q5.6(ix): Using IUPAC norms write the formulas for the following: Tetrabromidocuprate(II)
- Q5.6(v): Using IUPAC norms write the formulas for the following: Pentaamminenitrito-O-cobalt(III)
- Q5.6(vi): Using IUPAC norms write the formulas for the following: Hexaamminecobalt(III) sulphate
- Q5.6(vii): Using IUPAC norms write the formulas for the following: Potassium tri(oxalato)chromate(III)
- Q5.6(viii): Using IUPAC norms write the formulas for the following: Hexaammineplatinum(IV)
- Q5.6(x): Using IUPAC norms write the formulas for the following: Pentaamminenitrito-N-cobalt(III)
- Q5.7 (i): Using IUPAC norms write the systematic names: ([Co(NH_{3})_{6}]Cl_{3})
- Q5.7 (ii): Using IUPAC norms write the systematic names: ([Pt(NH_{3})_{2}Cl(NH_{2}CH_{3})]Cl)
- Q5.7 (iii): Using IUPAC norms write the systematic names: ([Ti(H_{2}O)_{6}]^{3+})
- Q5.7 (iv): Using IUPAC norms write the systematic names: ([Co(NH_{3})_{4}Cl(NO_{2})]Cl)
- Q5.7 (ix): Using IUPAC norms write the systematic names: ([Ni(CO)_{4}])
- Q5.7 (v): Using IUPAC norms write the systematic names: ([Mn(H_{2}O)_{6}]^{2+})
- Q5.7 (vi): Using IUPAC norms write the systematic names: ([NiCl_{4}]^{2-})
- Q5.7 (vii): Using IUPAC norms write the systematic names: ([Ni(NH_{3})_{6}]Cl_{2})
- Q5.7 (viii): Using IUPAC norms write the systematic names: ([Co(en)_{3}]^{3+})
- Q5.7(i): Using IUPAC norms write the systematic names of the following: \([Co(NH_{3})_{6}]Cl_{3}\)
- Q5.7(ii): Using IUPAC norms write the systematic names of the following: \([Pt(NH_{3})_{2}Cl(NH_{2}CH_{3})]Cl\)
- Q5.7(iii): Using IUPAC norms write the systematic names of the following: \([Ti(H_{2}O)_{6}]^{3+}\)
- Q5.7(iv): Using IUPAC norms write the systematic names of the following: \([Co(NH_{3})_{4}Cl(NO_{2})]Cl\)
- Q5.7(ix): Using IUPAC norms write the systematic names of the following: \([Ni(CO)_{4}]\)
- Q5.7(v): Using IUPAC norms write the systematic names of the following: \([Mn(H_{2}O)_{6}]^{2+}\)
- Q5.7(vi): Using IUPAC norms write the systematic names of the following: \([NiCl_{4}]^{2-}\)
- Q5.7(vii): Using IUPAC norms write the systematic names of the following: \([Ni(NH_{3})_{6}]Cl_{2}\)
- Q5.7(viii): Using IUPAC norms write the systematic names of the following: \([Co(en)_{3}]^{3+}\)
- Q5.8: List various types of isomerism possible for coordination compounds, giving an example of each.
- Q5.8: List various types of isomerism possible for coordination compounds, giving an example of each.
- Q5.9 (i): How many geometrical isomers are possible? ([Cr(C_{2}O_{4})_{3}]^{3-})
- Q5.9 (ii): How many geometrical isomers are possible? ([Co(NH_{3})_{3}Cl_{3}])
- Q5.9(i): How many geometrical isomers are possible in the following coordination entities? \([Cr(C_{2}O_{4})_{3}]^{3-}\)
- Q5.9(ii): How many geometrical isomers are possible in the following coordination entities? \([Co(NH_{3})_{3}Cl_{3}]\)
CBSE Solutions for Class 12 Chemistry Coordination Compounds
Chapters in CBSE - Class 12 Chemistry
Top Tutors who teach Coordination Compounds
Top Tutor
Rajouri Garden, Delhi
10 yrs of
Exp
1 student
8 hrs of classes completed
1200
per hour
Online Classes
Student's Home
Tutor's home
I believe in delivering concepts and knowledge from the scratch so as to make the subject easy and relatable. My target is not only marks but rather developing an interest in the students for the subjects so as to have a better understanding and a good prospect for the future.
Top Tutor
Karolan Ka Barh, Jaipur
10 yrs of
Exp
2 students
71 hrs of classes completed
700
per hour
Online Classes
Tutor's home
With 12 years of dedicated teaching experience, I have consistently aimed to deliver high-quality education in the field of Commerce and related subjects. Holding a B.Com, M.Com, and B.Ed, along with being UGC NET qualified, I have taught at various academic levels, ensuring conceptual clarity and practical understanding for students. My teaching approach emphasizes student engagement, real-life applications of theoretical knowledge, and consistent academic growth. I have successfully prepared students for board exams and competitive assessments, fostering both academic excellence and confidence. Throughout my career, I have remained committed to continuous learning and adapting to modern teaching methodologies.
Make complex topics easy to grasp and encourage the students and help in learning with such patient.
Top Tutor
Maan, Pimpri-Chinchwad
10 yrs of
Exp
6 students
263 hrs of classes completed
1200
per hour
Online Classes
Student's Home
Tutor's home
I have been teaching students for the past 10 years and have guided many to students in getting excellent results, showcasing their best performance. Concept-based teaching and an extra emphasis on every student needs has helped me provide a quality teaching environment to my students.
Top Tutor
Shivaji Nagar, Nagpur
15 yrs of
Exp
23 students
1018 hrs of classes completed
650
per hour
Online Classes
Withโ 15 year of teaching Experience in IIT-JEE, NEET, CBSE & STATE BOARD to teach physics Teaching is my passion, by my knowledge and experience I teach the student to in simple and interesting way so he/ she understand the subject very well. I have 4 years of teaching experience in online mode So that i understand wery well the challenge of online teaching. So that i develop different teaching style in online mode to explain the topic which can easily understand by student. I can teach from basic level to expertise level in subject My achievement is I taught more then 5000 thousand of student in offline and more then 1000 student in online classes of reputed coaching. My many student are in IIT, NITs, doing MBBS, also they score very well in Board examination. In on-line mode I want explore my self . Share my knowledge and experience with student of different part of country and connecting myself with new edge of education system that emerging very fast. If student follow my point to point guidelines, take regular class, do home work, give regular test, follow my teaching notes and shares their problem, ask doubts then he will definitely improved to expert level. If you believe in yourself you have a strong will power Commited to study which save your travel time and money then go for on-line class. Do hard work, no shortcut for success, It requires dedication, and passion to prove Best of luck ๐ค๐ ....
Really liked how vijay sir was able to explain difficult topics with relative ease and solved my doubts within the class itself.
Top Tutor
Banashankari, Bangalore
4 yrs of
Exp
5 students
271 hrs of classes completed
600
per hour
Online Classes
I am a commerce postgraduate from Pune University. Currently I am pursuing Ph.D in Commerce at one of the prestigious institutes for Commerce studies- Christ University, Bangalore. I have taught all the subjects of commerce to 11th & 12th Students since 4 years and BCom since 2 years. I have a good command on economics & accounts. I have a passion for teaching and have good understanding and practical exposure of these subjects. I also havd remotely worked as a Manager of Finance for a private firm in Maharashtra which makes me well versed in practical application of the subjects I teach.
Maam is very understanding. Explains concepts differently from school teaching making easy to learn and remember.
