When metal X is treated with a dilute acid Y, then a gas Z is evolved which burns readily by making a little explosion.

(a) Name any two metals which can behave like metal X.

(b) Name any two acids which can behave like acid Y.

(c) Name the gas Z.

(d) Is the gas Z lighter than or heavier than air ?

(e) Is the reaction between metal X and dilute acid Y, exothermic or endothermic ?

(f) By taking a specific example of metal X and dilute acid Y,write a balanced chemical equation for the reaction which takes place. Also indicate physical states of all the reactants and products.

Q.

The metal X reacts with dilute hydrochloric acid to form a gas Y.The metal X also reacts with sodium hydroxide solution (on heating) to form the same gas Y.When a lighted matchstick is applied,this gas burns by producing a 'pop' sound.

(a) Name two metals which could behave like X.

(b) Name the gas Y.

Q. Which gas is liberated when dilute hydrochloric acid reacts with zinc metal? Write a balanced chemical equation for the reaction which takes place. How will you test this gas? Name a metal which produces the same gas just by reacting with cold water.

Q. (a) What are metals? Name five metals.
(b) Name a metal which is so soft that it can be cut with a knife.
(c) Name the metal which is the best conductor of heat and electricity.
(d) What happens when a metal reacts with dilute hydrochloric acid? Explain with the help of an example.
(e) Write the equations for the reaction of:
(i) Magnesium with dilute hydrochloric acid
(ii) Aluminium with dilute hydrochloric acid
(iii) Zinc with dilute hydrochloric acid
(iv) Iron with dilute hydrochloric acid
Name the products formed in each case. Also indicate the physical states of all the substances involved.

Q. When a black metal compound XO is heated with a colourless gas Y₂, then metal X and another compound Y₂O are formed. Metal X is red-brown in colour which does not react with dilute acids at all. Gas Y₂ can be prepared by the action of a dilute acid on any active metal. The compound Y₂O is a liquid at room temperature which can turn anhydrous copper sulphate blue.
(a) What do you think is metal X?
(b) What could be gas Y₂?
(c) What is compound XO?
(d) What is compound Y₂O?
(e) Write the chemical equation of the reaction which takes place on heating XO with Y₂.
(f) What type of chemical reaction is illustrated in the above equation?

Q. A substance X which is used as an antacid reacts with dilute hydrochloric acid to produce a gas Y which is used in one type of fire-extinguisher. Name the substance X and gas Y. Write a balanced equation for the chemical reaction which takes place.