Hydrides of Group 16

Q. Given below are two statement:
Statement I:
The boiling points of the following hydrides of group $16$ elements increases in the order:
$H_{2}O<H_{2}S<H_{2}Se<H_{2}Te$
Statement II:
The boiling points of these hydrides increase with increase in molar mass.
In the light of the above statements, choose the most appropriate answer from the options given below:

1. Statement I is incorrect but Statement II is correct
2. Both Statement I and Statement II are correct
3. Both Statement I and Statement II are incorrect
4. Statement I is correct but Statement II is incorrect

Q.

The correct order of hydration enthalpies of alkali metal ions is

1. ${\mathrm{Li}}^{+}>{\mathrm{Na}}^{+}>{\mathrm{K}}^{+}>{\mathrm{Cs}}^{+}>{\mathrm{Rb}}^{+}$

2. ${\mathrm{Na}}^{+}>{\mathrm{Li}}^{+}>{\mathrm{K}}^{+}>{\mathrm{Rb}}^{+}>{\mathrm{Cs}}^{+}$

3. ${\mathrm{Li}}^{+}>{\mathrm{Na}}^{+}>{\mathrm{K}}^{+}>{\mathrm{Rb}}^{+}>{\mathrm{Cs}}^{+}$

4. ${\mathrm{Na}}^{+}>{\mathrm{Li}}^{+}>{\mathrm{K}}^{+}>{\mathrm{Cs}}^{+}>{\mathrm{Rb}}^{+}$

Q. Identify the incorrect statement, regarding the molecule $Xe{O}_4$.

1. $Xe{O}_4$ molecule is square planar
2. There are four $p\pi -d\pi$ bonds
3. There are four $s{p}^3-p$, $\sigma$ bonds
4. $Xe{O}_4$ molecule is tetrahedral

Q.

Which of the following gases turns lead acetate paper black?

1. ${\mathrm{SO}}_2$

2. ${\mathrm{SO}}_3$

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

4. ${\mathrm{H}}_2{\mathrm{SO}}_4$

Q. The decreasing order of bond angles in hydrides of chalcogens is:

1. $H_{2}O>H_{2}Te>H_{2}Se>H_{2}S$
2. $H_{2}S>H_{2}Se>H_{2}S>H_{2}Te$
3. $H_{2}O>H_{2}S>H_{2}Se>H_{2}Te$
4. $H_{2}Te>H_{2}Se>H_{2}S>H_{2}O$

Q.

What happens when S reacts with hot and conc. H2SO4?

Q.

Why phosphorus is stored in water?

Q. When $H_2{O}_2$ is oxidised by a suitable oxidant, the product is

1. $O^{2-}$
2. $H{O}^{2-}$
3. $O{H}^{-}$
4. $O_2$

Q.

List the chemical properties of carbon dioxide.

Q.

What is methane? Draw its electron dot structure. Name the type of bonds formed in this compound. Why are such compounds (i) Are poor conductors of electricity and (ii) Have low melting and boiling points? What happens when this compound burns in oxygen?

Q.

What is the relationship between steric hindrance and the rate of esterification?

Q.

Which one out of the following is divalent

1. Na

2. Al

3. Sr

4. None of these

Q. Identify the correct sequence of increasing number of $\pi$-bonds in the structures of the following molecules.
(I) $H_2{S}_2{O}_6$ (II) $H_{2}S{O}_3$ (III) $H_2{S}_2{O}_5$

1. I, II, III
2. II, III, I
3. II, I, III
4. I, III, II

Q.

${\mathrm{CH}}_3\mathrm{COOH}+{\mathrm{NaHCO}}_3\to {\mathrm{CH}}_3\mathrm{COONa}+{\mathrm{H}}_2\mathrm{O}+{\mathrm{CO}}_2$

The above reaction can be best confirmed by observing :

1. Precipitate formation

2. Bubble formation

3. Colour change

4. Temperature change

Q. What role does the molecular interaction play in a solution of alcohol and water?

Q. Compare the bond angles x and y in the following molecules:

1. $x>y$
2. None of these
3. $x=y$
4. $y>x$

Q.

The pH value of pure water is 7. Compare the pH values of (i) Sulphur dioxide solution and (ii) Ammonia solution with that of pure water.

Q. At normal temperature, $H_{2}O$ is liquid while $H_{2}S$ is a gas. Why?

Q. Consider the sequence of oxides: $N{a}_{2}O$, $Si{O}_2$, $P_4{O}_{10}$. Which factor decreases from $N{a}_{2}O$ to $Si{O}_2$ to $P_4{O}_{10}$?

1. Covalent character
2. Solubility in aqueous alkali.
3. pH when mixed with water
4. Melting point

Q. Assertion :Acidic character of group 16 hydrides increases from $H_{2}O$ to $H_{2}Te$. Reason: Thermal stability of hydrides decreases down the group.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. Oxygen is more electronegative than sulphur yet $H_{2}S$ is more acidic than $H_{2}O$. Because

1. $H_{2}S$ is a gas at ordinary temperature whereas $H_{2}O$ is a liquid
2. $H-S$ is weaker than $O-H$ bond
3. Stronger inter molecular $H$-bonding among $H_{2}O$
4. $H_{2}O$ has higher boiling point than $H_{2}S$

Q.

What is the effect of Hydrogen on litmus paper?

Q. Industrial name for $H_2{S}_2{O}_7$ is

1. Pyrosulphuric acid
2. Marshall’s acid
3. All
4. Oleum

Q. Arrange the following hydrides of group 16 elements in order of increasing stability:

1. $H_{2}S$ < $H_{2}O$ < $H_{2}Te$ > $H_{2}Se$
2. $H_{2}O$ < $H_{2}Te$ < $H_{2}Se$ < $H_{2}S$
3. $H_{2}O$ < $H_{2}S$ < $H_{2}Se$ < $H_{2}Te$
4. $H_{2}Te$ < $H_{2}Se$ < $H_{2}S$ < $H_{2}O$

Q.

State whether the following statements are true or false.

4. Oxygen is neutral towards litmus.

1. True
2. False

Q. Assertion :Hydrides of group-16 elements show volatility in the order : $H_{2}O>H_{2}S>H_{2}Se>H_{2}Te$ Reason: Electronegativity of group-16 elements increases down the group from oxygen to tellurium.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. $1.0g$ of magnesium is burnt with $0.56g{O}_2$ in a closed vessel. Which reactant is left in excess and how much?
$(\text{At. wt. Mg}=24;O=16)$

1. $\text{Mg},0.16g$
2. $O_2,0.16g$
3. $\text{Mg},0.44g$
4. $O_2,0.28g$

Q.

What is the action of hydrogen on litmus paper?

Q. Which of the folowing is incorrect?

1. $O_3$ is a powerful oxidising agent
2. Nitric oxide depletes ozone layer in upper atmosphere
3. Acidic strength increases from $H_{2}Te$ to $H_{2}O$
4. $S{O}_2$ is redusing agent while $Te{O}_2$ is an oxidising agent

Q. Which of the following compounds is most acidic?

1. $H_{2}O$
2. $H_{2}S$
3. $H_{2}Se$
4. $H_{2}Te$