Which of the following is (are) true when $\mathrm{HCl}\mathrm{ }\left(\mathrm{g}\right)$ is passed through water?

i. It does not ionize in the solution as it is a covalent compound.

ii. It ionizes in the solution

iii. It gives both hydrogen and hydroxyl ion in the solution

iv. It forms hydronium ion in the solution due to the combination of hydrogen ion with water molecule

Write a chemical equation for the reaction taking place in the flask. Write name and one property of the gas evolved.

State one observation for the following:

A small piece of zinc is added to dilute hydrochloric acid.

Which gas is produced during the reaction in the test tube? How does this gas react with calcium hydroxide/lime water?

State one relevant observation for of the following:

Lead nitrate solution is mixed with dilute hydrochloric acid and heated.

Which gas is usually liberated when an acid reacts with a metal? Illustrate with an example. How will you test for the presence of this gas?