Assuming benzene is immiscible with water and their normal boiling points are 80.1°C and 100°C respectively, what is the boiling point of their mixture at 1 atm total pressure__________________?
Show answer Hide answer
Answer: D. Greater than 80.1°C but less than 100°C
Explanation
Immiscible liquids exert independent vapor pressures that sum to the total pressure. The mixture boils when this combined vapor pressure equals the atmospheric pressure. Since individual vapor pressures are lower than total pressure, the boiling point drops. Dalton's law of partial pressures applies to immiscible vapor-liquid systems. Component liquids do not affect each other's escaping tendency in immiscible mixtures. Normal boiling points occur when individual vapor pressure reaches one atmosphere.
Steam distillation utilizes immiscible behavior to distill heat-sensitive organic compounds safely. Lowering the boiling point prevents thermal degradation of delicate natural extracts. Chemical engineering separation units utilize this phenomenon for purification processes. Option A represents the boiling point of pure benzene alone. Option B is incorrect because the boiling point remains above the more volatile component. Option C represents the normal boiling point of pure water alone.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. An azeotropic liquid mixture exhibits a boiling point lower than that of either pure component when it_____________?
Show answer Hide answer
Answer: D. Shows positive deviation from Raoult’s law
Azeotropes with boiling points lower than either component show positive deviations from Raoult. Positive deviations indicate weaker intermolecular forces between unlike molecules in solution. Such minimum-boiling azeotr...
Q2. The vapor pressure equation log10 P = A – B(t + c) is commonly known as the________________?
Show answer Hide answer
Answer: B. Antoine equation
The vapor pressure temperature relation containing logarithmic terms and constants is known as the Antoine equation. This empirical formula provides highly accurate calculations for vapor pressures across moderate temper...
Q3. When a metal oxide is reduced in a hydrogen stream, 3.15 g of the oxide produces 1.05 g of pure metal. From this, what can be deduced regarding the ____________________?
Show answer Hide answer
Answer: B. Equivalent weight of the metal is 4
The mass of oxygen combined with the metal is calculated by subtraction. Subtracting the metal mass from the oxide mass gives two point one grams. Equivalent weight is determined by scaling to eight grams of oxygen. Equi...
Q4. What is the approximate °API gravity of pure water at N.T.P__________________?
Show answer Hide answer
Answer: C. 10
API gravity formula uses specific gravity relative to water at standard conditions. Specific gravity of pure water is substituted as unity into the equation. Calculating this yields an API gravity value of exactly ten de...
Q5. At 100°C, both water and methylcyclohexane have vapour pressures of 1 atm. Their latent heats of vaporisation at 100°C are 40.63 kJ/mole and 31.55 kJ/mole respectively. Given water's vapour pressure is 4.69 atm at 150°C, the vapour pressure of methylcyclohexane at 150°C is expected to be _________________?
Show answer Hide answer
Answer: C. Significantly more than 4.69 atm
Applying thermodynamic vapor pressure relations like the Clausius Clapeyron equation evaluates pressure changes. Components with lower latent heats experience a steeper relative rise in vapor pressure with increasing tem...
Q6. Insulating refractory bricks require high porosity and low thermal conductivity. Which method is not employed to induce porosity during their production ?
Show answer Hide answer
Answer: C. Sand
Sand is a dense, high-density filler that increases bulk weight of refractories. Cork and sawdust burn out during firing to leave behind porous structures. Chemical foaming agents generate gas bubbles that create necessa...