Question

please answer this question

If 4 g of NaOH dissolves in 36 g of H2O, calculate the mole fraction of each component in the solution. Also, determine the molarity of solution (specificgravity of solution is 1 g mL–1).vu​

Answer 1

Mole fraction of H2O

= No.of moles of H2O/Total No.of moles (H2O + NaOH)

No. of moles of H2O = 36/18 = 2 moles

No. of moles NaOH = 4/40 = 0.1 mol

Total number of moles = 2+0.1 = 2.1

Mole fraction of H2O = 2/2.1 = 0.952

Mole fraction of NaOH = 0.1/2.1 = 0.048

Mass of solution

= Mass of H2O + Mass of NaOH = 36 + 4 = 40 g

Volume of solution = 40/1 = 40 mL

Molarity = No.of moles of solute/Volume of solution in L

= 0.1/0.04L = 2.5M

Answer 2

Answer:

Explanation:

`"4 g NaOH"=(4)/(40)"mole"="0.1 mole"`

`"36 g "H_(2)O=(36)/(18)"mole = 2 mole"`

`therefore " Mole fraction of "H_(2)P=1-0.047=0.953(or(2)/(2+0.1)=0.95)`

`"Total mass of solution "="Mass of solvent "+"Mass of solution"=36+4g=40g`

`"Volume of solution"=("Mass")/("Sp. gravity")=("40 g")/("1 g mL"^(-1))=40mL=0.040L`

`"Molarity of solution "=("Moles of solute")/("Volume of solution in L")=("0.1 mole")/("0.040 L")=2.5M`