Which of the following is a Lewis base ?

• NaOH

• NH₃

• BCl₃

• All of these

Which of the following dissolves in hot conc. NaOH solution?

• Fe

• Zn

• Cn

• Ag

283.

Which will make basic buffer?

• 100mL of 0.1 M CH₃COOH + 100mL of 0.1M NaOh

• 100 mL of 0.1 M HCl + 200 mL of 0.1 M NH₄OH

• 100 mL of 0.1 M HCl + 100 mL of 0.1 M NaOH

• 50 mL of 0.1 M NaOH + 25 mL of 0.1 M CH₃COOH

Conjugate base for BrÖnsted acids H₂O and HF are :

• H₃O⁺ and F^-, respectively

• OH^- and F^-, respectively

• H₃O⁺ and  H₂F⁺, respectively

• OH^- and H₂F⁺, respectively

pH of a saturated solution of Ca(OH)₂ is 9. The solubility product(K_sp) of Ca(OH)₂ is:

• 0.25 × 10^-10

• 0.5 × 10^-15

• 0.125 × 10^-15

• 0.5 × 10^-10

At 90⁰C , pure water has [H⁺]=10^-6 M , if 100 mL of 0.2 M HCl is added to 200mL of 0.1 M KOH at 90°C then pH of the resulting solution will be:

• 5

• 6

• 7

• 4

KMnO₄ can be prepared from K₂MnO₄ as per reaction

  $3{\mathrm{MnO}}_4^{2-} + 2{\mathrm{H}}_2\mathrm{O} \rightleftharpoons 2{\mathrm{MnO}}_4^{-} + {\mathrm{MnO}}_2 + 4{\mathrm{OH}}^{-}$

The reaction can go to completion by removing OH- ions by adding

• HCl

• KOH

• CO₂

• SO₂