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

723.

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

Consider the following reaction equilibrium:

${\mathrm{N}}_2\left(\mathrm{g}\right) +3{\mathrm{H}}_2\left(\mathrm{g}\right) \rightleftharpoons 2{\mathrm{NH}}_3\left(\mathrm{g}\right)$

Initially, 1 mole of N₂ and 3 moles of H₂ are taken in a 2 L flask. At equilibrium state if, the number of moles of N₂ is 0.6, what is the total number of moles of all gases present in the flask?

• 0.8

• 1.6

• 3.2

• 6.4