Boiling

Q.

What is the relationship between the vapour pressure and boiling point?

Q.

People add sodium chloride to water while boiling eggs. This is to______________.

Q.

Differentiate between the melting point and boiling point, giving at least one example of each.

Q. Calculate vapour pressure of 0.1M urea soln. Vapour pressure of water at the given temperature is 20 torr. Assume molality and molality to be equal.

Q.

What is the normal boiling point of water? At what pressure does water boils at this temperature?

Q.

Arrange the gases present in air in the ascending order of their boiling points: argon, oxygen, nitrogen.

Q.

What is the physical state of water at 100⁰C .

Q.

Why is $\mathrm{HCl}$ considered a polar covalent compound?

Q.

A liquid can change into vapour state

(a) at a fixed temperature, and

(b) at all temperatures

Name the processes involved in the two cases.

Q.

Explain the terms vaporization and boiling point.

Q.

Name the factors that affect the boiling point of a liquid.

Q.

Why a football inflated inside and then taken outdoors on a winter day shrinks slightly?

Q. Boiling and melting point of distilled water are _____ and _____ deg C respectively.

1. 0, 100
2. 4, 100
3. 100, 0
4. 100, 4

Q.

Which principle does pressure cooker use?

1. Increasing boiling point with steady vapour pressure

2. More vapour pressure, increase in boiling point

3. Decrease in vapour pressure, increase in boiling point

4. Less vapour pressure, decrease in boiling point

Q. Boiling point and melting point of a substance is 150 ${}^o$C and 50 ${}^o$C respectively. The temperature at which the substance undergoes freezing and condensation is X and Y respectively. Then:

1. X < 150 ${}^o$C
   Y < 50 ${}^o$C
2. X > 150 ${}^o$C
   Y > 50 ${}^o$C
3. X = 150 ${}^o$C
   Y = 50 ${}^o$C
4. X = 50 ${}^o$C
   Y = 150 ${}^o$C

Q.

Boiling water causes more severe burns than steam.

1. Steam

2. Boiling water

Q.

We use a pressure cooker to cook at high altitudes because of the following reason(s).

1. It increases the pressure inside the cooker.

2. It decreases the pressure inside the cooker.

3. it increases the boiling point of water.

4. it decreases the boiling point of water.

Q.

The temperature at which a liquid changes into its gaseous form is called ______

Q.

What makes water evaporate in vacuum....pls explain at molecular level and also how pressure affects change of state of matter....pls explain at molecular level

Q. Aldehydes and ketones have lower boiling points than corresponding alcohols and acids. Explain.

Q. Four beakers A, B, C and D with specific temperatures are shown. Which of the beakers are at equivalent temperature?

1. B and C
2. A and C
3. C and D
4. A and B

Q. Convert the following temperatures to the Celsius scale.
(a) $283k$ (b) $570k$

Q. Three alcohols - ethanol, propanol and butanol are mixed and heated for a long time in a beaker. Which is the last one to evaporate?

1. Ethanol
2. Propanol
3. Butanol
4. All evaporate at the same time

Q.

Solid $H_2$$O_2$ has non planar and non linear structure based on

1. Dipole moment

2. Chemical method

3. X-ray study

4. Both 1 & 2

Q.

Define the boiling point of water.

Q.

Kerosene contracts on heating.

1. True
2. False

Q.

Which of the following chemicals substance has the strongest hydrogen bond?

1. $\mathrm{HCl}$

2. ${\mathrm{H}}_2\mathrm{O}$

3. $\mathrm{HI}$

4. ${\mathrm{H}}_2\mathrm{S}$

Q. How is fractional distillation different from simple distillation?

Q. What is formed when a diamond is heated in vaccum?

Q.

Differentiate between evaporation and boiling.