Question

A student took a sample of a chemical and added acid to it, a gas is released which turned lime water milky. Which of the following option/options could be the chemical sample taken by the student?

• A. $NaHC{O}_3$
• B. $NaCl$
• C. $C_2{H}_6$
• D. $CaC{O}_3$

Answer 1

Answer: (A), (D)

The correct options are
A

$NaHC{O}_3$

D

$CaC{O}_3$

The chemical sample could be a carbonate or bicarbonate compound. When a carbonate or bicarbonate reacts with an acid $C{O}_2$ gas is released which turns lime water milky. The equation for the reaction between carbon dioxide and lime water is given below.

$Ca(OH{)}_2+C{O}_2\to CaC{O}_3+H_{2}O$

The $CaC{O}_3$ is called calcium carbonate and it is due to the formation of this compound that lime water turns milky.

This is a test to identify if a given salt is a carbonate or bicarbonate compound.