(i) 2.17 m , (ii) 6.25 M, (iii) 0.0376, (iv) 0.0826, (v) 8% (vi) 16.67%.

(vii) 25%, (viii) 36.25%, (ix) 72.5%, (x) 14.2 m.

(i) Molarity of NaOH = 2

Density = 1 g/ml

Let volume of solution = 1000 ml

∴ mass of solute = 2 × 40 = 80

Mass of solution = 1000 × 1 = 1000 g

Mass of solvent = 1000 – 80 = 920 g

molality = = 2.17

(ii) m = 5 Density = 1.5 g/ml

Let 1 Kg solvent

∴ mole of solute = 5

mass of solute = 5 × 40 = 200 g

Total mass of solution = 200 + 1000 = 1200 g

∴ Volume of solution = = = 800 ml

M = = 6.25

(iii) In (i) mole fraction of solute = = = = 0.0377

(iv) In (ii) mole fraction of solute = = = = 0.0826

(v) In (i) % (w/w) of NaOH = × 100 = 8 %

(vi) In (ii) % (w/w) of NaOH = × 100 = 16.67 %

(vii) In (ii) % (w/v) of NaOH = × 100 = 25 %

(viii) Mass of NaOH = 300 × + 500 × = 90 + 200 = 290 g

mass of solution = 300 + 500 = 800

% w/w of NaOH in mixture = × 100 = 36.25 %

(ix) Density of final solution = 2 g/ml

Volume of solution = = 400 ml

% w/v of NaOH = × 100 = 72.5 %

(x) In (vii) molality of final solution = = × 1000 = 14.2