(1) why should curd and sour substances not be kept in brass and copper
vessels?
(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.
Answers
1. Because curd and sour , which are acidic in nature will react with brass and copper which are metals , and it will harm us.
Answer:
1 sour substances should not be kept in brass and copper metals because, the acids present in the curd may react with brass and copper.
2. hydrogen gas, it's presence can be tested by placing a burning candle on the top of the flask in which the reaction is carried. If it produces a popping sound, it means hydrogen gas is produced.
3. the gas evolved is carbon di oxide. When calcium carbonate reacts with hydrochloric acid, the calcium and chloride combines to form calcium carbonate which releases carbon dioxide as by-product. the chemical equation is, CaCO
3
(s) + 2HCl(aq) → CaCl
2
(s) + CO
2
(g) + H
2
O(l)
hope it helps