Question

To prepare two litters of a solution containing 0.1 N Na₂CO₃, the amount of pure Na₂CO₃ needed is _____ g (MW of Na₂CO₃ = 106

The formula of S = (K_sp)^1/2cannot be used to calculate the solubility of:

		AgCl
		AgBr
		Ag2S
		AgI

A solution of 35.5 mg/L MgCl₂ mg/L contains _____ mg/L Cl^- (atomic weight: Mg = 24, Cl = 35.5).

A 0.01 N SO₄^2- has its concentration of ___ in the unit of meq/L.

Answer 1

1. Normality is defined as the equivalent wt. / volume of the solution

the mass of pure Na2CO3 required = 0.1 * 2* 106/2 = 10.6g

2.The formula of S = (Ksp)1/2 cannot be used to calculate the solubility of Ag2S

3. molar mass of MgCl2 = 95

also given concentration of solution = 35.5 mg/l

no. of moles = 0.3736

1 mole of MgCl2 = 2 gram atoms of Cl-

0.3736 moles = 0.7473 gram atoms of Cl-

therefore concentration = 0.7473 * 35.5 = 26.5315mg/l

4. A 0.01 N SO42- has its concentration of 0.01* in the unit of meq/L.