Among the following acids which has the lowest p_Ka value?

• CH₃COOH

• HCOOH

• (CH₃)₂COOH

• CH₃CH₂COOH

An ideal gas is allowed to expand both reversibly and irreversibly in an isolated system. If Ti is the initial temperature and Tf is the final temperature, which of the following statements is correct?

• (T_f)_irrev > (T_f)_rev

• T_f > T_i for reversible process but Tf = Ti for irreversible process

• (T_f)_rev = (T_f)_irrev

• T_f = T_i for both reversible and irreversible processes

At 25°C, the solubility product of Mg(OH)₂ is 1.0 × 10^–11. At which pH, will Mg²⁺ ions start precipitating in the form of Mg(OH)₂ from a solution of 0.001 M Mg²⁺ ions?

• 9

• 10

• 11

• 8

B.

10

Consider the reaction:
Cl₂(aq) + H₂S(aq) → S (s) + 2H⁺ (aq) + 2Cl^- (aq)
The rate equation for this reaction is
I. Cl₂ + H₂S → H⁺ +Cl^- + Cl⁺ +HS^-
II. H₂S ⇌ H⁺ + HS^- (fast equilibrium)
Cl₂ + HS^- → 2Cl^- + H⁺ + S (slow)

• II only

• Both (I) and (II)

• Neither (I) nor (II)

• (I) only

For a spontaneous reaction the ∆G, equilibrium constant (K) and E^o_cell will be respectively 

• -ve, >1, +ve

• +ve, >1, -ve

• -ve, <1, -ve

• -ve, >1, -ve