Question

1.Why should curd and sour substances not be kept in brass and copper
wessels?
2.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?
3.Metal compound A reacts with dilute hydrochloric acid to produce
effervescence. The gas evolved extinguishes a burning candle, Write a
balanced chemical equation for the reaction if one of the compounds
formed is calcium chloride.​

Answer 1

Explanation:

1 curd and sour substance should not be kept in brass and copper vessels because if any acidic food like curd if kept in brass or copper vessel they will react and forms toxic compounds which may harmful for stomach and can cause food poisoning.

2. hydrogen gas is usually liberated when metal reacts with acid.

for example -

2Na+2HCl----2Nacl+H2

3. balanced chemical equation -

CaCO3+2HCl---Cacl2+CO2+H2O

Answer 2

Answer:

1. Curd and sour substances should not be kept in copper or brass vessels , because they may react with the substances stored and make them toxic (since acids are sour in taste).
2. Hydrogen gas is mainly liberated when an acid reacts with metal.

eg.:- 2Al + 6HCl ――> 2AlCl3 + 3H2

3. CaCO3 + 2HCl ――> CaCl2 + CO2 + H2O