H₃PO₃ is

• dibasic acid

• basic

• tribasic acid

• neutral

542.

In an exothermic equilibrium ,

A + 3B $\rightleftharpoons$ AB₃

all the reactants and products are in gaseous state. The formation of AB₃ is favoured at :

• low temperature and low pressure

• low temperature and high pressure

• high temperature and high pressure

• high temperature and low pressure

A precipitate of AgCl is formed when equal volumes of the following are mixed :

[K_sp for AgCl = 10^-10]

• 10^-4 M AgNO₃ and 10^-7 M HCl

• 10^-5 M AgNO₃ and 10^-6 M HCl

• 10^-5 M AgNO₃ and 10^-4 M HCl

• 10^-6 M AgNO₃ and 10^-6 M HCl

The species among the following, which can act as an acid and a base is :

• HS${\mathrm{O}}_4^{2-}$

• S${\mathrm{O}}_4^{2-}$

• H₃O⁺

• Cl^-

If in the reaction N₂O₄ $\rightleftharpoons$ 2NO₂ , x is that part of N₂O₄ which dissociates, then the number of molecules at equilibrium will be :

• 1

• 3

• (1 + X)

• (1 + X)²

For the reaction, H₂ + I₂ $\rightleftharpoons$ 2HI, K = 47.6. If the initial number of moles of each reactant and product is 1 mole then at equilibrium

• [I₂] = [H₂] , [I₂] > [HI]

• [I₂] = [H₂] , [I₂] < [HI]

• [I₂] < [H₂] , [I₂] = [HI]

• [I₂] > [H₂] , [I₂] = [HI]

Calculate the overall complex dissociation equilibrium constant for the [Cu(NH₃)₄]²⁺ ions, given that stability  constant (${\mathrm{\beta }}_4$) for this complex is 2.1 $\times$ 10¹³.

• 8.27 $\times$ 10^-13

• 4.76 $\times$ 10^-14

• 2.39 $\times$ 10^-7

• 1.83 $\times$ 10¹⁴

The temperature dependence of a reaction is represented by the Arrhenius equation: 

ln k = -$\frac{{\mathrm{E}}_{\mathrm{a}}}{\mathrm{RT}}+\ln \mathrm{A}$

Which among the following is wrong conclusion about the given plot?

• Intercept of the line= ln A

• Slope = -$\frac{{\mathrm{E}}_{\mathrm{a}}}{\mathrm{RT}}$

• Reaction with high activation energy is more temperature sensitive than that of low activation energy (E_a).

• Slope = - $\frac{{\mathrm{E}}_{\mathrm{a}}}{\mathrm{R}}$

Which of the following oxoacids of phosphorus is a reducing agent and a monobasic acid as well?

• H₄P₂O₅

• HPO₃

• H₃PO₃

• H₃PO₂

K_a for HCN is 5 x 10^-10 at 25°C. For maintaining a constant pH = 9, the volume of 5 M KCN solution required to be added to 10 mL of 2 M HCN solution is

• 4 mL

• 2.5 mL

• 2 mL

• 6.4 mL