Exams › JEE Main › Chemistry

When copper(II) sulphate solution is treated with excess potassium cyanide, the product formed is:

1. Cu(CN)2
2. CuCN
3. K2[Cu(CN)2]
4. K3[Cu(CN)4]

Correct answer: K3[Cu(CN)4]

Solution

Cu2+ oxidises CN- to cyanogen and is itself reduced to Cu(I), which with excess cyanide forms the soluble complex K3[Cu(CN)4].

Related JEE Main Chemistry questions

• A transition metal M gives a volatile chloride whose vapour density is 94.8. If this chloride contains 74.75% chlorine by mass, what is the formula of the metal chloride?
• What is the ratio of the magnetic moments of Fe(III) and Co(II)?
• Which of the following species contains the greatest number of unpaired electrons?
• Which of the following species contains an atom in the +6 oxidation state?
• Which of the following pairs contains compounds in which the metal in each case is present in its maximum possible oxidation state?
• Among the following metal oxides, which one exhibits antiferromagnetic behavior?

⚔️ Practice JEE Main Chemistry free + battle 1v1 →