An ideal solution is formed by mixing 23g C2H5OH with 16.0g of CH3OH at the same temperature. The vapour pressures of pure C2H5OH and CH3OH are 40mm of Hg and 80mm of Hg respectively and total vapour pressure of the solution is x cm of Hg. Find x .

Question

An ideal solution is formed by mixing 23g C2H5OH with 16.0g of CH3OH at the same temperature. The vapour pressures of pure C2H5OH and CH3OH are 40mm of Hg and 80mm of Hg respectively and total vapour pressure of the solution is x cm of Hg. Find x . (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

n C 2 H 5 OH =(23/46)=(1/2) ⋅ n CH 3 OH =(16/32)=(1/2) PA=PA0 × XA ⇒ PA=40 × (1/2)=20 m ⋅ n PB=PBρ ⇒ PB=80 × (1/2)=40 m ⋅ n +60 m ⋅ n =6 cm

Q. An ideal solution is formed by mixing 23g C2​H5​OH with 16.0g of CH3​OH at the same temperature. The vapour pressures of pure C2​H5​OH and CH3​OH are 40mm of Hg and 80mm of Hg respectively and total vapour pressure of the solution is xcm of Hg. Find x .

nC2​H5​OH​=4623​=21​⋅nCH3​OH​=3216​=21​ PA​=PA0​×XA​⇒PA​=40×21​=20m⋅n PB​=PBρ​⇒PB​=80×21​=40m⋅n+60m⋅n=6cm

$n_{C_{2} H_{5} O H} = \frac{23}{46} = \frac{1}{2} \cdot n_{C H_{3} O H} = \frac{16}{32} = \frac{1}{2}$
$P_{A} = P_{A}^{0} \times X_{A} \Rightarrow P_{A} = 40 \times \frac{1}{2} = 20 m \cdot n$
$P_{B} = P_{B}^{ρ} \Rightarrow P_{B} = 80 \times \frac{1}{2} = 40 m \cdot n + 60 m \cdot n = 6 c m$