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 _______.

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)

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

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

The correct order of the calculated spin-only magnetic moments of complexs (A) to (D) is:
(A) Ni(CO)₄
(B) [Ni(H₂O)₆]Cl₂
(C) Na₂[Ni(CN)₄]
(D) PdCl₂(PPh₃)₂