Properties of Oxygen

Q.

Give reason why PbCl2 is more stable than PbCl4

Q.

Why hydrogen gas is not released when nitric acid is reacted with zinc

Q. Thermal decomposition of $AgN{O}_3$ produces two paramagnetic gases. The total number of electrons present in the antibonding molecular orbitals of the gas that has the higher number of unpaired electrons is.

Q.

Name two gases that dissolve in water to some extent.

Q.

Why is ${\mathrm{PbO}}_2$ not a peroxide?

Q.

Can burning takes place in the absence of oxygen ? Explain.

Q. A mixture of two moles of carbon monoxide and one mole of oxygen, in a closed vessel is ignited to convert the carbon monoxide to carbon dioxide. If $\Delta H$ is the enthalpy change and $\Delta E$is the change in internal energy, then

1. $\Delta H>\Delta E$
2. $\Delta H<\Delta E$
3. $\Delta H=\Delta E$

4. The relationship depends on the capacity of the vessel

Q. Among primary, secondary and tertiary, which alcohol is more soluble in water??

Q.

Which of the following compounds is used in antiknock compositions to prevent the deposition of oxides of lead on spark plug, combustion chamber and exhaust pipe

1. Glycerol

2. Glycol

3. 1, 2-dibromoethane

4. Benzene

Q.

Which of the following are products of combustion of a fuel

1. Oxygen

2. Carbon dioxide

3. Water

4. Nitrogen

Q.

State any two conditions for the conversion of sulphur dioxide to sulphur trioxide.

Q.

Write the trends in the valency of elements in a group.

Q.

Is Mo paramagnetic or diamagnetic?

Q.

Define thermal expansion of gases.

Q. acidic oxide among the following is (a)NO (b)CO (c)Na2o (d)Cl2O7

Q. Which is the most abundant group $16$ element?

1. Oxygen
2. Sulphur
3. Selenium
4. Tellurium

Q. Which of the following statement is incorrect for group $15$ elements?

1. Tendency to exhibit $-3$ oxidation state decreases down the group
2. Tendency to exhibit $+5$ oxidation state increases down the group
3. All of the above
4. Tendency to exhibit $+3$ oxidation state increases down the group

Q. Show $O_2$ is a paramagnetic.

Q.

What is used as a cathode in a Leclanche cell?

1. Graphite rod surrounded by powdered MnO₂ and carbon

2. Zinc container

3. Graphite rod covered by a paste of NH₄Cl and ZnCl₂

4. None of the above

Q.

Name three metals that are used in atomic energy and space projects.

Q.

The density of hot air is_____ than that of cold air.

Q.

During electrolysis of molten lead bromide, graphite anode is preferred to other electrodes. Give reasons.

Q. Correct the following statements:
(g) Metals absorb hydrogen.

Q. Explain why $O_2$ molecule is paramagnetic in nature ?

Q. Which of the following will favour the decomposition of $KCl{O}_3$?

1. $V_2{O}_5$
2. $Mn{O}_2$
3. $F{e}_3{O}_4$
4. $Ni$

Q. Potassium permanganate $\to$ potassium manganate + $A$ + oxygen.
What is $A$ in the given reaction?

1. Manganese dioxide
2. Manganese
3. Manganese trioxide
4. Manganese tetraoxide

Q.

4. Carbon dioxide is used for extinguishing fires caused by petroleum products but not fires caused by metals like Na or Mg. Explain.

Q.

8. Assertion (A): Hydrogen gas is one of the components in both oxyhydrogen flame and oxyacetylene flame.

Reason (R): Hydrogen is inflammable.

1. Both (A) and (R) are true and (R) is the correct reason of (A).

2. Both (A) and (R) are true but (R) is not the correct reason of (A).

3. (A) is true but (R) is false

4. (A) is false but (R) is true.

Q. Oxygen is a neutral gas which supports combustion.

1. True
2. False

Q.

Assertion (A): Carbon shows tetravalency in the compounds.

Reason(R): Atoms attain the nearest inert gas configuration during bonding.

1. Both A and R are true and R is the correct explanation of A.

2. Both A and R are true, but R is not the correct explanation of A.

3. A is true and R is false.

4. A is false and R is true.