Question

The colour of an aqueous solution of a salt is deep green, what is the basic radical of the salt?
(A) Calcium
(B) Cobalt
(C) Manganese
(D) Copper

Answer 1

Hint:As we have learnt that salt analysis is the process of identification of cations and anions present in an inorganic salt. By checking the colour of the salt the cation can be identified and if the salt is colourless the flame test can be conducted.

Complete answer:As we know that salt analysis or systematic quantitative analysis helps in identification of a cation or anion which are present in an inorganic salts. We can conduct a preliminary test for the given unknown salt by checking its colour, odour or even taste.
The colour test of certain inorganic salts results in the identification of the cations. For instance: the blue colour or pale green as well as deep green colour of unknown inorganic salt represents the copper cation, green colour is also used for the reference of nickel cation. Brown or yellow colour of inorganic salt is for iron, deep blue represents cobalt, pale pink colour represents manganese and purple or dark green represents chromium cation in the given unknown inorganic salt.
So when these inorganic salts are dissolved into water they result in the same colour formations. So the colour of an aqueous solution of a salt which is deep green represents the copper in salt.

Therefore the correct answer is (D).

Note:Copper compounds possess different colours in different solutions like copper oxides are black in colour, copper hydroxides are generally pale blue and gelatinous in nature, copper sulphate is crystallised bright blue compound. Copper carbonate is bluish green powdery solid and copper chloride is commonly present as a light green solid.