Question

the strength of an aqueous solutions of sodium nitrate is 0.425 g/25ml

Answer 1

Hello Dear.

Answer ⇒ Option B. 0.2 M (or 0.2 mol/L)

Solutions ⇒ 

Given ⇒
Mass of the Sodium Nitrate = 0.425 grams.
Volume of the Solution = 25 ml.
 = 25/1000 liter.
 = 0.025 liter.

Molar Mass of Sodium Nitrate = 85 g/mol.
[∵ 23 + 14 + 3 × 16 = 85]

∵ No. of moles of Sodium Nitrate(NaNO₃) = Mass/Molar Mass
   = 0.425/85
   = 0.005 g


Now,
∵ Molarity of the Solution = No. of moles of Sodium Nitrate ÷ Volume of the Solutions in liter.
 = 0.005/0.025
 = 0.2 M.


Thus, the Molarity of the Solution is 0.2 M. (or 0.2 mol/L). Hence, Option B. is Correct.


Hope it helps.