Question

Give a chemical test to distinguish between the following. Calcium nitrate and zinc nitrate.

Answer 1

The reagent that we use for distinguishing the compounds is a strong base, or an alkali. On reaction, one compound gives a white precipitate, whereas the other compound does not give the solubility.

Complete answer:
In order to answer our question, let us know some facts about sodium hydroxide solution. Sodium hydroxide solution which is also called caustic soda, is an inorganic compound which has the chemical formula NaOH. It is a white solid which turns out to be an ionic compound consisting of $N{{a}^{+}}$ cations and $O{{H}^{-}}$ anions.
Sodium hydroxide is a very strong base, or an alkali and alkali that decomposes proteins at ordinary room temperatures and causes severe chemical burns. It has a very good solubility in water and absorbs carbon dioxide present in the air. It can form a variety of hydrates too, due to its very good solubility in water.
Crystallisation of sodium hydroxides from water solutions between 12.3 and 61.8 degrees. The commercially available "sodium hydroxide" is present in the form of monohydrate. As one of the simplest hydroxides, it is used in the neutralisation reaction as a base to provide salt and water.
Now, in order to distinguish between the two compounds, we add sodium hydroxide solution to both of them. In case of zinc nitrate, a white coloured precipitate is formed. This is soluble when sodium hydroxide is present in excess. However, a precipitate is formed which is not soluble in the solution.

Note:
Apart from sodium hydroxide, ammonium hydroxide solution can also be used to distinguish. Precipitation results are generally the same. The reaction is:
$\begin{aligned} & Zn{{(N{{O}_{3}})}_{2}}+2N{{H}_{4}}OH\to Zn{{(OH)}_{2}}+2N{{H}_{4}}N{{O}_{3}} \\\ & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(white\,ppt) \\\ \end{aligned}$