Question

The salt reacts with dil. HCl giving colourless gas with brisk effervescence. indicates the presence of ____ radical.

a) Cl-
b) NO3-
c) SO42-
d) CO32-​

Answer 1

Answer:

d) carbonate radical CO32-

Answer 2

When HCl reacts with a salt giving brisk effervescence

Explanation:

• When a salt is treated with dilute HCl a brisk effervescence of a colorless gas is evolved which indicates the presence of carbonate, sulphide, sulphite, nitrite and acetate ions.
• When carbonate ion is present it indicates the release of a colorless, odourless CO₂ gas which turns lime water milky.
• Confirmatory test for carbonate ion is-
• There will be evolution of colorless and odourless gas with brisk                                   effervescence on addition of dilute HCl to the solid salt, thus it indicates the  presence of carbonate ion. This gas turns lime water milky because of the formation of CaCO₃. If this gas passed in excess then milkiness which is produced disappears due to the formation of calcium bicarbonate which is soluble in water.

So, Option(d) is correct i.e. CO₃²⁻.