Which of the following compounds are in the correct sequence in terms of relative basic strength?

1. \(C_{2} H_{5} O^{-} > CH \equiv C^{-} > \left(OH\right)^{-}\)

2. \(CH \equiv C^{-} >(OH)^{-} > C_{2} H_{5} O^{-}\)

3. \(CH \equiv C^{-} > C_{2} H_{5} O^{-} > \left(OH\right)^{-}\)

4. \(C_{2} H_{5} O^{-} > \left(OH\right)^{-} > CH \equiv C^{-}\)

Among the following examples, the species that behave(s) as a Lewis acid is/are: 
\(\mathrm{BF}_3, \mathrm{SnCl}_2, \mathrm{SnCl}_4\)

1. Stannous chloride, Stannic chloride
2. $B{F}_3$, Stannous chloride
3. Only $B{F}_3$
4. $B{F}_3$, Stannous chloride, Stannic chloride

The rapid change of pH near the stoichiometric point of an acid-base titration is the basis of indicator detection. pH of the solution is related to the ratio of the concentrations of the conjugate acid (\(HIn\)) and base (\(In^–\)) forms of the indicator, as per the expression:

The solubility of AgCl in 0.2 M magnesium chloride will be $\left({\mathrm{K}}_{sp}<mspace\; width="1em"></mspace>\mathrm{of}<mspace\; width="1em"></mspace>\mathrm{AgCl}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>1.8<mspace\; width="1em"></mspace>\mathrm{x}<mspace\; width="1em"></mspace>{10}^{-10}\right)$

1.  1.8 x ${10}^{-10}$

2.  1.8 x ${10}^{-11}$

3.  9 x ${10}^{-10}$

4.  4.5 x ${10}^{-10}$

The equilibrium constant of the reaction A₂(g) + B₂(g) $\rightleftharpoons$ 2AB (g) at 100ºC is 50.  If a one litre flask containing one mole of A₂ is connected to a two litre flask containing two moles of B₂, how many moles of AB will be formed at 373 K ?

1. 2.8

2. 1.9

3. 2.1

4. 3.6

A buffer solution is defined as a solution whose pH remains practically constant even when small amounts of an acid or a base are added to it.
Henderson's equation is used to determine pH of buffer mixtures of different types: 
For acidic buffer, Henderson's equation is :
pH= pK_a + log \([Salt] \over [Acid]\)   (k_a = ionisation constant of weak acid)

For basic buffer, Henderson's equation is : 
POH = Pk_b + log \([Salt] \over [Base]\)  (k_b = ionisation constant of weak base)

How many moles of HCl are required with 0.01 mole NaCN to prepare a buffer solution of pH =9? 
[Given: K_a of HCN = \(1 \times 10^{-10}\)]

1. 0.009

2. 0.09

3. 0.9

4. Buffer solution cannot formed

The pH of 10^-6 M CH₃COOH will be:
(Given: k_a of CH₃COOH = 1.8 \(\times\) 10^-5  & log 4.24 =0.63)

1. 5.37

2. 7.0

3. Slightly more than 6

4. 6.95

What can be the active mass of CaCO₃ if 10 grams of CaCO₃ are taken in a one-liter container?
[Given: Molecular weight of CaCO₃ = 100]

1. 0.1 

2. 1 

3. 0.01 

4. 10