Question

The density of 2 M aqueous solution of NAOH is 1.28g/
${cm}^{3}$
.The molarity of the solution is

Answer 1

Answer:0.001m or 0.001mol/kg

Explanation:3M=3 moles of solute present in 1L of solution

aqueous solution of NaOH means solute is NaOH and solvent is water

we know that,density(solution)=mass(solution)/ volume(solution)

1.28g/mL^3=mass(solution)/1L

1.28g/mL^3×1000mL=mass (solution)

1280g=mass (solution)

molecular mass of solute NaOH= 23×1+16×1+1=40

no. of moles(solute)=mass in gram(solute)/ molecular mass(solute)

2=mass in gram (solute)/40

mass in gram (solute)=80

mass of solvent

=mass of solution-mass of solute

mass of solvent=1280-80=1200

molality=moles of solute/mass of solvent(in kg)

molality=2/1200 =0.001m or 0.001mol/kg

I HOPE YOU WILL UNDERSTAND