Factors Affected by Hydrogen Bonding

Q. Arrange in decreasing order of acid strength.

$HF,HCl,HBr,HI$

1. $HF>HCl>HBr>HI$

2. $HCl>HBr>HI>HF$

3. $HI>HBr>HCl>HF$

4. $HBr>HI>HCl>HF$

Q. Why H2O is a liquid while H2S is a gas

Q. The correct order of boiling point is:

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

Q.

The correct order of thermal stability of hydrogen halides (H – X) is

1. HF >HCl>HBr> HI

2. HCl> HF >HBr> HI

3. HI >HCl> HF >HBr

4. HI >HBr>HCl> HF

Q.

The correct order of acidic strength of HOCl, HClO2, HClO3 and HClO4 are:

Q.

While separating a mixture of ortho and para nitrophenols by steam distillation, name the isomer which will be steam volatile. Give reason.

Q.

Why ice is lighter than water?

Q.

If the boiling point of H₂O is 373 K, the boiling point of H₂S will be

1. Greater than 300 K but less than 373 K

2. Equal to 373 K

3. More than 373 K

4. Less than 300 K

Q. Assertion:o-nitrophenol is a weaker acid than p-nitrophenol. Reason: Intramolecular hydrogen bonding makes ortho isomer weaker than para isomer.

Q.

Why does an acidic strength increase down the group?

Q. The carboxylic acid which has maximum solubility in water is:

1. Phthalic acid
2. Malonic acid
3. Succinic acid
4. Salicylic acid

Q.

Question 04

Hydrogen bonds are formed in many compounds e.g., $H_{2}O,HF,N{H}_3$. The boiling point of such compounds depends to a extent on the strength of hydrogen bond and the number of hydrogen bonds. The correct decreasing order of the boiling points above compounds is

(a) $HF>H_{2}O>N{H}_3$

(b) $H_{2}O>HF>N{H}_3$

(c) $N{H}_3>HF>H_{2}O$

(d) $N{H}_3>H_{2}O>HF$

Q. Arrange the following types of interactions in order of their increasing stability.

1. Hydrogen < van der Waals force < Covalent bonding
2. van der Waals force < Hydrogen bonding < Covalent
3. Covalent <van der Waals force< Hydrogen bonding
4. van der Waals force<Covalent <Hydrogen bonding

Q. $o$-nitrophenol is more volatile than $p$-nitrophenol because of:

1. Steric hindrance
2. Hyperconjugation
3. Resonance
4. Intra-molecular H-bonding

Q.

Use the information and date given below to answer the question (a) to (c),

Stronger intermolecular forces result in higher boiling point.

Strength of London forces increases with the number of electrons in the molecule.

Boiling point of HF, HCl, HBr and Hi are 293 k, 189 k, 206 k and 238 k respectively.

(a) Which type of intermolecular forces are present in the molecules HF, HCl, HBr an HI?

(b) Looking at the trend of boiling points of HCl, HBr and HI, explain out of dipole-dipole interaction and London interaction, which one is predominant here.

(c) Why is boiling point of hydrogen fluoride highest while that of hydrogen chloride lowest?

Q.

Sugar is soluble in water due to:

1. High solvation energy

2. Hydrogen bond formation with water

3. High dipole moment of water

4. Ionic charachter of sugar

Q.

Are alcohols capable of hydrogen bonding?

Q.

The boiling point of methanol, water and dimethyl ether are respectively ${65}^{0}C,{100}^{0}Cand{34.5}^{0}C$. Which of the following best explains these wide variations in b.p.?

1. The extent of H-bonding decreases from water to methanol while it is absent in ether

2. The extent of intramolecular H-bonding decreases from ether to methanol to water

3. The molecular mass increases from water (18) to methanol (32) to diethyl ether (74)

4. The density of water is 1.00 g ml^-1, methanol 0.7914 g ml^-1 and that of diethyl ether is 0.7137 g ml^-1

Q.

Alcohols are comapratively more soluble in water than hydrocarbons of comparable molecular masses. Explain this fact.

Q.

In solid argon, the atoms are held together by

1. Ionic bonds

2. Hydrogen bonds

3. Van der Waals forces

4. Hydrophobic forces

Q. H2SO4 has higher viscosity than water. Reason being bonding.

1. intermolecular H-
2. intramolecular H-
3. covalent

Q.

Bond angle in is higher than that in PH₃. Why?

Q.

Do Ethers have Dipole Dipole Forces?

Q. The correct order of boiling point is:

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

Q. 28. How many 1^°, 2^°, 3^° H atoms are present in toluene ?

Q. Two isomers of c3H6O

Q. How hcp and FCC have same packing fraction?

Q.

Explain why propanol has higher boiling point than that of the hydrocarbon, butane?

Q. The correct order of hydrogen bond strength and boiling point respectively is

1. $HF>H_{2}O,H_{2}O>HF$
2. $HF>H_{2}O,HF>H_{2}O$
3. $H_{2}O>HF,H_{2}O>HF$
4. $HF>H_{2}O,HF=H_{2}O$

Q.

Question 34.1

Structures of molecules of two compounds are given below.

Which of the two compounds will have intermolecular hydrogen bonding and which compound is expected to show intramolecular hydrogen bonding?

(ii) The melting point of the compound depends on, among other things, the extent of hydrogen bonding. On this basis explain which of the above two compounds will show higher melting point?

(iii) The solubility of compounds in water depends on power to form hydrogen bonds with water. Which of the above compounds will form a hydrogen bond with easily and be more soluble in it?