Question

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.
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Answer 1

Answer:

1. 1.Fresh milk does not contain lactic acid. ... Hence when these acids react with metals they give salt and hydrogen. If these kinds of substances which possess acids are kept in copper containers or vessels they will react and produce salt and hydrogen and the vessel will be corroded

2.Hydrogen gas is liberated when an acid reacts with a metal. For example, when zinc metal reacts with dil. hydrogen is evolved and salt zinc chloride is formed as: It can be tested by bringing a burning candle near the gas. 3. The gas thus formed is an effervescent carbon dioxide gas when calcium carbonate reacts with hydrochloric acid. The carbon dioxide gas also acts as an extinguisher for fires. Hence, the burning candle is extinguished. The metal compound A, therefore, constitutes calcium carbonate.