Avogadro's Law & Gay Lussac's Law

Q. A vessel having a volume of 5 litres contains $1.4\text{g}$ of nitrogen at a temperature of $1800\text{K}$. The pressure of the gas if 30% of its molecules are dissociated into atoms at this temperature is:

1. $4.05\text{atm}$
2. $3.84\text{atm}$
3. $2.025\text{atm}$
4. $1.92\text{atm}$

Q. Four one litre flasks are separately filled with the gases, $O_2,F_2,C{H}_4$ and $C{O}_2$ under the same conditions. The ratio of number of molecules in these gases:

1. $2:2:4:3$
2. $1:1:1:1$
3. $1:2:3:4$
4. $2:2:3:4$

Q. Equal volumes of $H_2$ and $C{l}_2$ are mixed. How will the volume of the mixture changes after the reaction at same T and P?

1. Unchanged
2. Reduced to half
3. None of these
4. Increases two fold

Q. An open vessel at ${27}^{o}C$ is heated until ${\frac{3}{8}}^{th}$ of the air in it has been expelled. Assuming that the volume remains constant, calculate the temperature to which the vessel was heated.

1. ${480}^{o}C$
2. ${207}^{o}C$
3. ${307}^{o}C$
4. ${107}^{o}C$

Q. A gas mixture of 3 litres of propane $\left(C_3{H}_8\right)$ and butane $\left(C_4{H}_{10}\right)$ on complete combustion at ${25}^o$ produced 10 litre $C{O}_2.$ Find out the composition of gas mixture (Propane : Butane)

1. $3:1$
2. $1:2$
3. $1:1$
4. $2:1$
   

Q. What is the volume occupied by 0.25 moles of $N{H}_3$ gas at STP?

1. $11200\text{mL}$
2. $5600\text{mL}$
3. $8590\text{mL}$
4. $22400\text{mL}$

Q. The ratio of masses of oxygen and nitrogen in a particular gaseous mixture is $1:4$. Their ratio of number of molecules is:

1. $1:4$
2. $7:32$
3. $1:8$
4. $3:16$

Q. An amount of 1.00 g of a gaseous compound of boron and hydrogen occupies 0.820 litre at 1.00 atm and at $3^{\circ }C.$ The compound is ($R=0.0820L$ atm mol${}^{-1}{K}^{-1}$, Atomic weight: H = 1.0, B = 10.8)

1. $B{H}_3$
2. $B_2{H}_6$
3. $B_3{H}_{12}$
4. $B_4{H}_{10}$

Q. Two closed vessel $A$ and $B$ of equal volume containing air at pressure $P_1$ and temperature $T_1$ are connected to each other through a narrow open tube. If the temperature of one is now maintained at $T_1$ and other at $T_2$ (where $T_1>T_2$) then that what will be the final pressure?

1. $\frac{T_1}{2P_1{T}_2}$
2. $\frac{2P_1{T}_2}{T_1+T_2}$
3. $\frac{2P_1{T}_2}{T_1-T_2}$
4. $\frac{2P_1}{T_1+T_2}$

Q. The ratio of masses of oxygen and nitrogen in a particular gaseous mixture is $1:4$. The ratio of number of their molecule is: $x:y$. Find the value of $x+y$

Q.

If 100 cm³ of oxygen contain Y molecules, how many molecules of nitrogen will be present in 50 cm³ of nitrogen under same conditions of temperature and pressure.

Q.

One gram mole of a gas at STP occupies 22.4L volume. This fact was derived from –

1. None of the above

2. Daltion’s theory

3. Avogadro’s hypothesis

4. Berzelius' hypothesis

Q. If the pressure of the gas contained in a closed vessel is increased by $20\%$ when heated by $273{}^{\circ }\text{C}$ then, its initial temperature must have been:

1. $1052{}^{\circ }\text{C}$
2. $1029\text{K}$
3. $1365{}^{\circ }\text{C}$
4. $1365\text{K}$

Q. One mole of $N_2{O}_4\left(g\right)$ at $300\text{K}$ and $1.0atm$ is kept in a closed container. It is heated to $600\text{K}$ when $20\%$ by mass of $N_2{O}_4\left(g\right)$ decomposes to $N{O}_2\left(g\right)$. The resultant pressure is:

1. 2.4 atm
2. 1.2 atm
3. 2.0 atm
4. 1.0 atm

Q. Which of the following hydride does NOT follow the Law of definite proportions?

1. $NaH$

2. $PdH$

3. $Ca{H}_2$

4. $LiH$

Q. 0.75 mol of solid $X_4$ and 2 mol of $O_2$ are heated in a closed container to form only one gaseous compound. The ratio of final pressure at ${327}^{\circ }C$ to the initial pressure at ${27}^{\circ }C$ in the flask is ?

1. 0.75
2. 1
3. 1.5
4. 2

Q. The ratio of masses of oxygen and nitrogen in a particular gaseous mixture is $1:4$. Their ratio of number of molecules is:

1. $1:4$
2. $7:32$
3. $1:8$
4. $3:16$

Q. 0.75 mol of solid $X_4$ and 2 mol of $O_2$ are heated in a closed container to form only one gaseous compound. The ratio of final pressure at ${327}^{\circ }C$ to the initial pressure at ${27}^{\circ }C$ in the flask is ?

1. 0.75
2. 1
3. 1.5
4. 2

Q.

A cylinder containing cooking gas can withstand a pressure of 15 atm. The pressure gauge of the cylinder indicates 12 atm at ${27}^{\circ }C$. Due to a sudden fire in the building, the temperature starts rising. At what temperature will the cylinder explode?

1. ${88}^{\circ }C$

2. ${116}^{\circ }C$

3. ${102}^{\circ }C$

4. ${108}^{\circ }C$

Q. If $v$ is the volume of one molecule of a gas under given conditions, then van der Waals constant 'b' is : ($N_0$ = Avogadro's number)

1. $4v$
2. $\frac{4v}{N_0}$
3. $\frac{N_0}{4v}$
4. $4v{N}_0$

Q.

The temperature of a gas placed in an open container is raised from ${27}^{\circ }to{227}^{\circ }C.$ The percent of the original amount of the gas expelled from the container will be ?

1. 20

2. 40

3. 60

4. 80

Q. The freezing point depression constant for water is $–1.86°C{m}^{–1}$. If 5.00 g $N{a}_{2}S{O}_4$ is dissolved in $45.0g$ $H_{2}O$, the freezing point is changed by $–3.82°C$. Calculate the van’t Hoff factor for $N{a}_{2}S{O}_4$.

1. 2.05
2. 0.381
3. 2.63
4. 3.11

Q.

One gram mole of a gas at STP occupies 22.4L volume. This fact was derived from –

1. Daltion’s theory

2. Avogadro’s hypothesis

3. Berzelius' hypothesis

4. None of the above

Q. Equal volumes of $H_2$ and $C{l}_2$ are mixed. How will the volume of the mixture changes after the reaction at same T and P?

1. Unchanged
2. Reduced to half
3. Increases two fold
4. None of these

Q. The freezing point depression constant for water is $–1.86°C{m}^{–1}$. If 5.00 g $N{a}_{2}S{O}_4$ is dissolved in $45.0g$ $H_{2}O$, the freezing point is changed by $–3.82°C$. Calculate the van’t Hoff factor for $N{a}_{2}S{O}_4$.

1. 2.63
2. 2.05
3. 0.381
4. 3.11

Q. A vessel having a volume of $5$ litres contains $1.4\text{g}$ of nitrogen at a temperature of $1800\text{K}$. The pressure of the gas if $30\%$ of its molecules are dissociated into atoms at this temperature is:

1. $4.05\text{atm}$
2. $2.025\text{atm}$
3. $3.84\text{atm}$
4. $1.92\text{atm}$

Q. A gas is present above and below the piston in a cylinder fitted with movable piston having a certain mass. On both sides of the piston there are equal number of moles of gas. The volume above is two times the volume below at a temperature of $300\text{K}$. At what temperature will the volume above be four times the volume below?

1. $600\text{K}$
2. $400\text{K}$
3. $200\text{K}$
4. $120\text{K}$

Q. van der Waals' constant '$b$' of $Ar$ is $3.22\times {10}^{-5}{\text{m}}^3{\text{mol}}^{-1}$. Calculate the molecular diameter(in $nm$) of $Ar$.

1. 0.35
2. 0.43
3. 0.29
4. 0.17