For an electrochemical cell

Sn(s) | Sn²⁺ (aq,1M)||Pb²⁺ (aq,1M)|Pb(s)

the ratio $${{\left[ {S{n^{2 + }}} \right]} \over {\left[ {P{b^{2 + }}} \right]}}$$ when this cell attains equilibrium is _________.

(Given $$E_{S{n^{2 + }}|Sn}^0 = - 0.14V$$,

$$E_{P{b^{2 + }}|Pb}^0 = - 0.13V$$, $${{2.303RT} \over F} = 0.06$$)

In the following sequence of reactions the maximum number of atoms present in molecule 'C' in one plane is _________. (A is a lowest molecular weight alkyne)

NaClO₃ is used, even in spacecrafts, to produce O₂. The daily consumption of pure O₂ by a person is 492L at 1 atm, 300K. How much amount of NaClO₃, in grams, is required to produce O₂ for the daily consumption of a person at 1 atm, 300 K?
NaClO₃(s) + Fe(s) $$ \to $$ O₂(g) + NaCl(s) + FeO(s)
R = 0.082 L atm mol^–1 K^–1

At constant volume, 4 mol of an ideal gas when heated from 300 K to 500K changes its internal energy by 5000 J. The molar heat capacity at constant volume is _______.