This set of Physical Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “Hydrogen Molecule Ion”.
1. What is the concentration of H+ ion in a solution of 0.1 NaOH?
a) 10-13 M
b) 10-13 M2
c) 9-13 M
d) 9-13 M2
View Answer
Explanation: By the principle of ion product concept of water,
The ion product of water is Kw = [H+][OH–] = 1×10-14 M2
Since, the concentration of OH– ions is 0.1 so, after substituting it in the above equation and rearrange for [H+] we get,
[H+] = Kw / [OH–] = 1×10-14 M2 / 0.1 M = 10-13 M.
2. What happens to the acid when Ka decreases?
a) Acid will be more stronger
b) Acid will be more weaker
c) Acid will be converted to neutral solution
d) Acid will be converted to basic solution
View Answer
Explanation: Ka is the dissociation constant of acids and bases. Higher values of Ka means, the acids or bases are readily dissociated to release corresponding H+ and OH- ions respectively. Thus, strong acids will have higher values of Ka than weak acids. Since, negative log of Ka is called pKa so, higher the pKa value, weaker will be the acids.
3. Why the movement of H+ ions in water to negatively charge electrode is extremely faster than Na+ and K+ ions?
a) H+ ions are more positive than Na+ or K+ ions
b) H+ ions are smaller than Na+ or K+ ions
c) H+ ions can move in water very fast by proton tunneling
d) H+ ions can move in water very fast by proton hopping
View Answer
Explanation: Water has a slight tendency if ionization. Water molecules ionize into H+ and OH– ions. The H+ ions formed can immediately combine to intact H2O to form hydronium ion (H3O+). This hydronium ion migrates to cathode because of the electric current by proton hopping.
4. Which of the following molecule does not form hydrogen bond with water?
a) –O –H
b) –N –H
c) –C –H
d) –S –H
View Answer
Explanation: To form hydrogen bond with water there is a need of dipole forces in between the atoms. Since, there is no significant difference between the electronegativity of C and H and hence they cannot produce a dipole. And therefore, –C –H does not form hydrogen bond with water.
5. How is CO2 transported through the blood in the body?
a) CO2 hemoglobin complex
b) CO2 myoglobin complex
c) CO2 bubbles
d) As bicarbonate
View Answer
Explanation: CO2 is primarily transported as bicarbonate through the blood in the body. Carbon dioxide forms carbonic acid (H2CO3) in aqueous solution and is transported as the HCO3- (bicarbonate) ions. Free bicarbonate is readily soluble in water.
6. Which of the following is very high for proton?
a) Radius
b) Ionization potential
c) Charge
d) Hydration energy
View Answer
Explanation: Because of the small size of protons, they possess high hydration energy. The size of cation decides the degree of hydration. Therefore, smaller the size of cation, higher will be its hydration energy.
7. Which of the following statement is true about hydrogen and chlorine molecules?
a) Hydrogen molecule can’t participate in coordination bond formation while chlorine molecule can
b) Hydrogen molecule can form intermolecular hydrogen bonds but chlorine does not
c) Hydrogen molecule is polar while chlorine molecule is non-polar
d) Hydrogen molecule is non-polar but chlorine molecule is polar
View Answer
Explanation: Chlorine consists of lone pair of electrons plus empty d orbitals. Thus, it can form coordination covalent bonds. Hydrogen molecule does not contain any lone pair of electrons, so they cannot form coordination bonds. Hence, hydrogen cannot participate in coordination bond formation.
8. Why H+ ion always associate with other atoms or molecules?
a) Because its size reduces
b) Because it somehow resembles both alkali metals and halogens
c) Its reactivity is very similar to halogens
d) Ionization enthalpy of hydrogen is almost same as that of alkali metals
View Answer
Explanation: When an electron lost from an atom of hydrogen, this results in the decrease of size of nucleus as compared to other atoms. Because of its small size it can never exist free and thus, H+ ion tends to associate with other atoms or molecules.
9. Ortho hydrogen is an isotope of hydrogen.
a) True
b) False
View Answer
Explanation: Hydrogen has three naturally occurring isotopes, denoted as protium (1H), deuterium (2H) and tritium (3H). Ortho hydrogen is not an isotope of hydrogen. Ortho hydrogen molecules are those in which the spins of both the nuclei are in same direction.
10. What is the bond length between H and O atoms in water?
a) 0.00965 nm
b) 0.0965 nm
c) 0.965nm
d) 9.650 nm
View Answer
Explanation: The H-O bond length is about 0.96 Å (ångström). The H-O-H bond angle is about 104.5 degrees. Vibrational normal modes are located at 3756 cm-1 (symmetric stretch), 3657 cm-1 (anti-symmetric stretch).
Sanfoundry Global Education & Learning Series – Physical Chemistry.
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