`K_1 and K_2` are the first and second dissociation constants of oxalic acid. Choose the correct statement –

What is dissociation constant of a weak acid (K_(a)) .

The first ionisation constant of oxalic acid is much greater than its second ionisation constant. Justify.

K_(a_(1)), K_(a_(2)) and K_(a_(3)) are the three dissociation constants of H_3PO_4 . Which of the following is a correct order

H_3PO_4 (Phosphoric acid) is a tribasic acid. In aqueous solution it ionises in the following three steps H_3PO_4overset(k_1)iffH^++H_2PO_4^- , H_2PO_4^(-)overset(k_2)iffH^++HPO_4^(2-) , HPO_4^(2-)overset(k_3)iffH^++PO_4^(3-) . Here K_1,K_2,K_3 are the dissociation constants of the respective three steps. The correct order of the values of three constants is

If K_(a) and K_(b) are the dissociation constants of weak acid and its conjugate base , pK_(a) + pK_(b)