Answer:
B.) He added a base to raise the PH
Explanation:
Took test
Answer:
The correct answer to this question is (c) 25.0 m
Explanation:
To solve this we list out the variables thus
mole fraction of sodium hydroxide = 0.310
Mole fraction = number of moles of a component ÷ total number of moles in the solution
Mole fraction = 0.310
In a saturaturated aqueous solution we have NaOH and water
∴ Number of moles of water molecules per unit = 1 - 0.310 = 0.690
However 0.690 moles of H₂O weighs = 0.690 mole × 18.01528 g/mol =12.43 g = 0.01243 kg of H₂O
But the molality = number of moles per Kilogram of H₂O
therefore molality of NaOH in the sample of solution =
(0.310 mol of NaOH )÷(0.01243 kg of H₂O)
= 24.93 mol/kg or ≅ 25.0 m
