The molar solubility of ${\mathrm{CaF}}_2$ $({\mathrm{K}}_{\mathrm{sp}}=5.3$ $\mathrm{\times }$ ${10}^{-11})$ in 0.1 M solution of NaF will be:

1.	$5.3$ $\mathrm{\times }$ ${10}^{-11}$ $\mathrm{mol}$ ${\mathrm{L}}^{-1}$	2.	$5.3$ $\mathrm{\times }$ ${10}^{-8}$ $\mathrm{mol}$ ${\mathrm{L}}^{-1}$
3.	$5.3$ $\mathrm{\times }$ ${10}^{-9}$ $\mathrm{mol}$ ${\mathrm{L}}^{-1}$	4.	$5.3$ $\mathrm{\times }$ ${10}^{-10}$ $\mathrm{mol}$ ${\mathrm{L}}^{-1}$

Which of the following cannot act both as a Bronsted acid and as a Bronsted base?

1. H₃O⁺ and H₂F⁺, respectively.

2. OH^– and H₂F⁺, respectively.

3. H₃O⁺ and F^–, respectively.

4. OH^– and F^–, respectively.

Which composition will make the basic buffer?

The hydrogen ion concentration of a 10^-8 M HCl aqueous solution at 298 K (K_w = 10^-14) is:

1. \(1 . 0 \times \left(10\right)^{- 6}\) \(M\)

2. \(1 . 0525 \times \left(10\right)^{- 7}\) \(M\)

3. \(9 . 525 \times \left(10\right)^{- 8}\) \(M\)

4. \(1 . 0 \times \left(10\right)^{- 8}\) \(M\)

The following pair constitutes a buffer is:

1. $HN{O}_2$ $and$ $NaN{O}_2$

2. $NaOH$ $and$ $NaCl$

3. $HN{O}_3$ $and$ $N{H}_{4}N{O}_3$

4. $HCl$ $and$ $KCl$

For the reaction, 
CH₄(g) + 2O₂(g) CO₂(g) + 2H₂O(l) 
Δ_rH = -170.8 kJ mol^-1 
Which of the following statements is not true?
 

Which one of the following orders correctly represents the increasing acid strengths of the given acids?

1. $HOCl<HOClO<HOCl{O}_2<HOCl{O}_3$

2. $HOClO<HOCl<HOCl{O}_3<HOCl{O}_2$

3. $HOCl{O}_2<HOCl{O}_3<HOClO<HOCl$

4. $HOCl{O}_3<HOCl{O}_2<HOClO<HOCl$