For the redox reaction:
$$MnO_4^ - + {C_2}O_4^{ - 2} + {H^ + }$$ $$ \to M{n^{2 + }} + C{O_2} + {H_2}O$$
The correct coefficients of the reactants for the balanced reaction are

A 2.0 g sample of a mixture containing sodium carbonate, sodium bicarbonate and sodium suplphate is gently heated till the evolution of CO₂ ceases. The volume of CO₂ at 750 mm Hg pressure and at 298K is measured to be 123.9 ml. A 1.5g of the same sample requires 150 ml. of (M/10) HCl for complete neutralisation. Calculate the % composition of the components of the mixture.

One gram of commercial AgNO₃ is dissolved in 50 ml. of water. It is treated with 50 ml. of a KI solution. The silver iodide thus precipitated is filtered off. Excess of KI in the filterate is titrated with (M/10) KIO₃ solution in presence of 6M HCl till all I^- ions are converted into ICl. It requires 50 ml. of (M/10) KIO₃ solution. 20 ml. of the same stock solution of KI requires 30 ml. of (M/10) KIO₃ under similar conditions. Calculate the percentage of AgNO₃ in the sample.
(Reaction : KIO₃ + 2KI + 6HCl $$\to$$ 3ICl + 3KCl + 3H₂O)

Which of the following relates to photons both as wave motion and as a stream of particles?