Which branched chain isomer of the hydrocarbon with molecular mass 72u gives only one isomer of mono substituted alkyl halide ?

The pH of a 0.1 molar solution of the acid HQ is 3. The value of the ionization constant, K_a of this acid is :

The equilibrium constant (K_C) for the reaction N₂(g) + O₂(g) $$\to$$ 2NO(g) at temperature T is 4 $$\times$$ 10^–4. The value of K_C for the reaction, NO(g) $$\to$$ 1/2N₂(g) + 1/2O₂(g) at the same temperature is :

The standard reduction potentials for Zn²⁺/ Zn, Ni²⁺/ Ni, and Fe²⁺/ Fe are –0.76, –0.23 and –0.44 V respectively. The reaction

X + Y²⁺ $$\to$$ X²⁺ + Y will be spontaneous when :