Question

how many grams of sodium hydroxide are required to dissolve in 232 g of water to make a 2.88 m solution

Answer 1

Grams of Sodium hydroxide : 26.72 g

Further explanation

Molality shows the number of moles dissolved in every 1000 grams of solvent.

m = n. (1000 / p)

m = Molality

n = Number of moles of solute

p = Solvent mass (gram)

Can be written :

$\tt m=\dfrac{mol~solute}{kg~solvent}$

• mol solute(NaOH)

m=2.88

kg solvent(water)=232 g=0.232 kg

$\tt mol~solute=m\times kg~solvent\\\\mol~solute=2.88\times 0.232=0.668$

• mass of NaOH

$\tt mass=mol\times MW\\\\mass=0.668\times 40~g/mol=26.72~g$