Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below. (b) Write a balanced chemical equation for the reaction taking place.

Give reasons
(b) Sodium, potassium and lithium are stored under oil.

You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.

Differentiate between metal and non-metal on the basis of their chemical properties.

You are given a hammer, a battery, a bulb, wires and a switch. (a) How could you use them to distinguish between samples of metals and non-metals?

Food cans are coated with tin and not with zinc because

A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?

An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be

Name two metals which will displace hydrogen from dilute acids, and two metals which will not.

Which of the following pairs will give displacement reactions?

In the electrolytic refining of a metal $M$, what would you take as the anode, the cathode and the electrolyte?

Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below.
(a) What will be the action of gas on
(i) dry litmus paper?

You are given a hammer, a battery, a bulb, wires and a switch. (b) Assess the usefulness of these tests in distinguishing between metals and non-metals.

Give reasons
(d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction.

State two ways to prevent the rusting of iron.

What type of oxides are formed when non-metals combine with oxygen?

What are amphoteric oxides? Give two examples of amphoteric oxides.

Give reasons
(a) Platinum, gold and silver are used to make jewellery.

Which of the following methods is suitable for preventing an iron frying pan from rusting?

Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron).