Metals and Non-Metals — Science STD 10 — Question

What happens during a wasp sting? What is its remedy?

Write the balanced chemical equations for the following reaction.
Copper sulphate on treatment with potassium iodide precipitates cuprous iodide (Cu₂I₂), liberates iodine gas and also forms potassium sulphate.

What happens when wood is burnt in a limited supply of oxygen? Name the residue left behind after the reaction and state two advantages of using this residue as a fuel over wood.

Translate the following statements into chemical equations and then balance them.

1. Hydrogen gas combines with nitrogen to form ammonia.
2. Hydrogen sulphide gas burns in air to give water and sulpur dioxide.
3. Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.
4. Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.

A gas ‘X’ reacts with lime water and forms a compound ‘Y’ which is used as a bleaching agent in chemical industry. Identify ‘X’ and ‘Y’. Give the chemical equation of the reactions involved.

Write an equation to show the reaction between Plaster of Paris and water.

State reasons for the following observations:
Metal sulphides occur mainly in rocks but metal halides occur mostly in sea and lake waters.

P and Q are aqueous solutions of sodium chloride and sodium hydroxide, respectively. Which of these will turn:

1. Blue litmus red?
2. Red litmus blue?

Which of the following are endothermic reactions and which are exothermic reactions?

1. Burning of natural gas.
2. Photosynthesis.
3. Electrolysis of water.
4. Respiration.
5. Decomposition of calcium carbonate.

A solution of a substance ‘X’ is used for white washing.

1. Name the substance ‘X’ and write its formula.
2. Write the reaction of the substance ‘X’ named in (i) above with water.