Answer:
(D) Na₂SO₄•10H₂O (M = 286).
Explanation:
- The depression in freezing point of water by adding a solute is determined using the relation:
<em>ΔTf = i.Kf.m,</em>
Where, ΔTf is the depression in freezing point of water.
i is van't Hoff factor.
Kf is the molal depression constant.
m is the molality of the solute.
- Since, Kf and m is constant for all the mentioned salts. So, the depression in freezing point depends strongly on the van't Hoff factor (i).
- van't Hoff factor is the ratio between the actual concentration of particles produced when the substance is dissolved and the concentration of a substance as calculated from its mass.
(A) CuSO₄•5H₂O:
CuSO₄ is dissociated to Cu⁺² and SO₄²⁻.
So, i = dissociated ions/no. of particles = 2/1 = 2.
B) NiSO₄•6H₂O:
NiSO₄ is dissociated to Ni⁺² and SO₄²⁻.
So, i = dissociated ions/no. of particles = 2/1 = 2.
(C) MgSO₄•7H₂O:
MgSO₄ is dissociated to Mg⁺² and SO₄²⁻.
So, i = dissociated ions/no. of particles = 2/1 = 2.
(D) Na₂SO₄•10H₂O:
Na₂SO₄ is dissociated to 2 Na⁺ and SO₄²⁻.
So, i = dissociated ions/no. of particles = 3/1 = 3.
∴ The salt with the high (i) value is Na₂SO₄•10H₂O.
So, the highest ΔTf resulted by adding Na₂SO₄•10H₂O salt.
Answer:
A. boiling point
Explanation:
The correct answer is;
A. boiling point
The boiling point of a liquid is the temperature at which the vapour pressure is equal to the atmospheric pressure.
B. melting point
This option is wrong because the melting point is the temperature at which a solid undergoes a phase change to a liquid.
C. freezing point
This option is wrong because the freezing point is the temperature at which a liquid undergoes a phase change to a solid.
Answer:
B or C
Explanation:
I don't really know sorry.
Answer:
Option 5.
Equal amounts of hydroxide and hydronium ions
Explanation:
2H₂O ⇄ H₃O⁺ + OH⁻ Kw: 1×10⁻¹⁴
Neutral solution has pH = 7
So, [H₃O⁺] = [OH⁻]
In solutions of only pure water:
[H₃O⁺] = 1×10⁻⁷ M
[OH⁻] = 1×10⁻⁷ M
Kw = [H₃O⁺] . [OH⁻] → 1×10⁻⁷ . 1×10⁻⁷ = 1×10⁻¹⁴
Answer:
cis-1,3-dibromocyclohexane
Explanation:
