MCQ on Water, Hydrogen Bonds, pH Scale and Buffer Systems Part 2 (Biochemistry MCQ-12)


MCQ on Hydrogen Bond, pH Scale

(Sample/Model/Practice Questions for CSIR JRF/NET Life Science Examination, ICMR JRF Exam, DBT BET JRF Exam,, GATE BT and XL Exam, ICAR JRF NE Exam, PG Entrance Exam, JAM Exam, GS Biology Exam and Medical Entrance Exam)

(1). Bond length between H and O atoms in water is:

a.       0.00965 nm
b.      0.0965 nm
c.       0.965 nm
d.      9.650 nm

(2). The van der Waals radius of Oxygen atom in water molecule is

a.       1.2 Å
b.      1.4 Å
c.       1.6 Å
d.      1.8 Å

(3). At room temperature and atmospheric pressure, a single water molecule can be hydrogen bonded with __________ water molecules.

a.       3.4
b.      3.0
c.       2.4
d.      1.4

(4). Non polar molecules are insoluble in water. This is because:

a.       Non polar molecules are uncharged
b.      Non polar molecules cannot be ionized
c.       Non polar molecules are unable to form water-solute interaction
d.      Hydrogen bond formation is not possible with non-polar molecules

(5). Which of the following is the correct for the formation of a hydrogen bond? (Hydrogen bond is represented as ‘…’)

a.       – O – H – O – H – X
b.      – O – H … O – X
c.       – O – H … H – O – X
d.      – O – H … C – O – X

(6). Which of the following statement is true? The number of inter-molecular hydrogen bonds between water molecules will be:

a.       Maximum in ice and minimum in water vapor
b.      Maximum in liquid water and minimum in water vapour
c.       Minimum in liquid water and maximum in water vapour
d.      Same in ice, liquid water and water vapour

(7). What is the concentration of H+ ion in a solution of 0.1 M NaOH?

a.       10-13 M
b.      9-13 M
c.       10-13 M2
d.      9 –13 M2

(8). As the Ka of an acid decreases, the acid will be

a.       More weaker
b.      More stronger
c.       Converted to neutral solution
d.      Converted to basic solution

(9). Which of the following molecule do not form hydrogen bond with water?

a.       – O – H
b.      – N – H
c.       – C – H
d.      – S – H

(10). Hydrogen bond will be strongest when the bonded molecules oriented to maximize the electrostatic interaction, which can occur when:

a.       The hydrogen atom and the two atoms that share it are in the same molecule
b.      The hydrogen atom and the two atoms that share it are in separate molecule
c.       The hydrogen atom and the two atoms that share it are in very close contact
d.      The hydrogen atom and the two atoms that share it are in a straight line

(11). Which of the following statement is true?

a.       CO2, O2 and N2 are non-polar and completely insoluble in water
b.      CO2, O2 and N2 are polar and soluble in water
c.       CO2 and O2 and N2 are partially soluble in water
d.      CO2 and O2 are polar and soluble in water, but N2 is non-polar and insoluble in water

(12). CO2 in our body is transported through the blood primarily as:

a.       CO2 bubbles
b.      CO2 hemoglobin complex
c.       CO2 myoglobin complex
d.      As bicarbonate

(13). Which of the following statement is true regarding the solubility of NH3, NO and H2S in water?

a.       All are completely non polar and insoluble in water
b.      All are polar and completely soluble in water
c.       NH2 and H2S are polar but NO is non-polar
d.      NH3 and H2S are non-polar but NO is polar

(14). When amphipathic compounds are mixed with water,

a.       It can readily dissolve in water
b.      It can form two separate layers in water
c.       It can form micelles in water
d.      It can increase the solubility of water

(15). Movement of H+ ions in water to negatively charge electrode (cathode) is extremely faster than Na+ or K+ ions, this is because:

a.       H+ ions are smaller than Na+ or K+ ions
b.      H+ ions are more positive than Na+ or K+ ions
c.       H+ ions can move in water very fast by proton hopping
d.      H+ ions can move in water very fast by proton tunneling


Biology / Life Sciences MCQ: Biochemistry MCQ-12: (Multiple Choice Questions / Model Questions / Sample Questions in Biochemistry: Water and pH Part 2 with detailed answer key, explanations and references for preparing CSIR JRF NET Life Science Examination and also for other competitive examinations in Life Science / Biological Science such as ICMR JRF Entrance Exam, DBT BET JRF Exam, GATE (XL) Life Science Exam, GATE (BT) Biotechnology Exam, ICAR JRF Exam, University PG Entrance Exam, JAM Exam, GS Biology Exam, GRE, Medical Entrance Examination etc. This set of practice questions will help to build your confidence in Biochemistry to face the real examination. A large quantum of questions in our practice MCQ is taken from previous year question papers of various national and international Biology / Life Sciences competitive examinations. Please take advantage of our Lecture Notes, PPTs, Previous Year Questions, Mock Tests, and Video Tutorials for your preparation. You can download all these questions papers and study materials as PDF from our Slideshare account absolutely free


Answer Key, Explanations and References

(1). Ans. (b). 0.0965 nm

(2). Ans. (b). 1.4 Å

(3). Ans. (a). 3.4

(4). Ans. (c).  Non polar molecules are unable to form water-solute interaction

(5). Ans. (b). – O – H … O – X

(6). Ans. (a). Maximum in ice and minimum in water vapor

(7). Ans. (a). 10-13 M

For the calculation we have to use the ion product concept of water

The ion product of water Kw = [H+][OH-] = 1 X 10-14 M2

We know the concentration of OH- ions as 0.1

Substitute in the above equation and rearrange for [H+]

i.e., [H+] = Kw / [OH-] = 1 X 10-14 M2 / 0.1 M

= 10-14M2/10-1M

= 10-13M

(8). Ans. (a). More weaker

Ka is the dissociation constant of acids and bases. Higher values of Ka means, the acids of bases are readily dissociated to release corresponding H+ or OH- ions. Thus strong acids will have higher values of Ka than weak acids. The negative log of Ka is called pKa. Sine pKa is negative log of Ka, higher the pKa value, the weaker will be the acids.

(9). Ans. (c). – C – H

There is no significant difference between the electronegativity of C and H and hence they cannot produce a dipole.

(10).  Ans. (d). The hydrogen atom and the two atoms that share it are in a straight line

(11).  Ans. (a). CO2, O2 and N2 are non-polar and completely insoluble in water

(12).  Ans. (d). As bicarbonate

Carbon dioxide forms carbonic acid (H2CO3) in aqueous solution and is transported as the HCO3- (bicarbonate) ions. Free bicarbonate is readily soluble in water.

(13).  Ans. (b). All are polar and completely soluble in water

(14).  Ans. (c). It can form micelles in water

(15).  Ans. (c). H+ ions can move in water very fast by proton hopping.

Water has a slight tendency of 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 can migrate to cathode under the electric current by proton hopping.

Reference: (1). Lehningers Principles of Biochemistry: Chapter: Water
                        (2). Fundamentals of Biochemistry by Voet and Voet: Chapter: Water

The answer key is prepared with best of my knowledge.
You are requested to inform me if there is any mistakes in the answer key or more clarifications if any.


MCQ on Water, pH and Buffer    |  Part – 1  | Part – 3  |


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