Question

An ore on treatment with dilute hydrochloric acid produces brisk effervescence. From the following list what type of ore is this?
[Sulfide, Carbonate, Phosphate, Nitrate]

Answer 1

Hint- In order to solve the problem and find out the type of ore first we will see the gas that may have been produced. Then on the basis of gas produced we will see the type of ore and also the chemical reactions involved if any.

Complete answer:
As we know that brisk effervescence means $C{O_2}$ is produced.
Since the ore gives brisk effervescence on reacting with dilute hydrochloric acid, it is likely to be a carbonate ore.
When an ore on the treatment with the dilute hydrochloric acid produces brisk effervescence to produce a colorless and odorless gas then the ore should be carbonate ore. The operation required to obtain metal from it will be a calcination process.
For example:
$ZnC{O_3}\left( s \right) \to ZnO\left( s \right) + C{O_2}\left( g \right)$
Hence, the given ore is a carbonate ore.

Note- Calcination process is when the metal carbonates on treatment with the dilute hydrochloric acid, it releases carbon dioxide as a colorless and odorless gas with brisk effervescence. By the calcination process the metal carbonate ore is converted to their metal oxides. The common varieties of carbonate ore are calcite, dolomite and aragonite are prominent constituents of certain rocks: calcite is the principal mineral of limestone and marbles; dolomite occurs as a replacement for calcite in limestone.