The electronic configuration of $$\mathrm{Cu}(\mathrm{II})$$ is $$3 \mathrm{~d}^9$$ whereas that of $$\mathrm{Cu}(\mathrm{I})$$ is $$3 \mathrm{~d}^{10}$$. Which of the following is correct?

In qualitative test for identification of presence of phosphorous, the compound is heated with an oxidising agent. Which is further treated with nitric acid and ammonium molybdate respectively. The yellow coloured precipitate obtained is :

Iron (III) catalyses the reaction between iodide and persulphate ions, in which

A. $$\mathrm{Fe}^{3+}$$ oxidises the iodide ion

B. $$\mathrm{Fe}^{3+}$$ oxidises the persulphate ion

C. $$\mathrm{Fe}^{2+}$$ reduces the iodide ion

D. $$\mathrm{Fe}^{2+}$$ reduces the persulphate ion

Choose the most appropriate answer from the options given below:

Arrange the following elements in the increasing order of number of unpaired electrons in it.

(A) $$\mathrm{Sc}$$

(B) $$\mathrm{Cr}$$

(C) $$\mathrm{V}$$

(D) $$\mathrm{Ti}$$

(E) $$\mathrm{Mn}$$

Choose the correct answer from the options given below :