In following pairs, the one in which both transition metal ions are colourless is :

Concentrated $$\mathrm{HNO}_{3}$$ reacts with Iodine to give

Which of the following has least tendency to liberate $$\mathrm{H}_{2}$$ from mineral acids?

For kinetic study of the reaction of iodide ion with $$\mathrm{H}_{2} \mathrm{O}_{2}$$ at room temperature :

(A) Always use freshly prepared starch solution.

(B) Always keep the concentration of sodium thiosulphate solution less than that of KI solution.

(C) Record the time immediately after the appearance of blue colour.

(D) Record the time immediately before the appearance of blue colour.

(E) Always keep the concentration of sodium thiosulphate solution more than that of KI solution.

Choose the correct answer from the options given below :