This set of Biochemistry Multiple Choice Questions & Answers (MCQs) focuses on “Water as a Reactant”.
1. A) CuSO4 + 5H2 O CuSO4.5H2 O
B) PCl3 + 3H2 O H3 PO3 + 3HCl
The processes A and B are respectively
a) Hydration and dehydration
b) Hydration and hydrolysis
c) Hydrolysis and hydrolysis
d) Hydration and hydration
Explanation: Process A involves absorption of water and B involves double decomposition reaction.
2. Which of the following is not a condensation reaction?
a) ADP + inorganic phosphate ATP + H2O
b) R-OH + inorganic phosphate phosphate ester + H2 O
c) R-COOH + inorganic phosphate Acyl phosphate + H2 O
d) 6CO2 + 6 H2 O C6 H12 O6 + 6CO2
Explanation: Condensation reaction involves elimination of water molecules.
3. Which of the following is the correct equation?
a) CO2 + H2 O H2 CO3
b) CO2 + H2 O HCO3
c) CO2 + H2 O H3 CO3
d) CO2 + H2 O H2 CO2
Explanation: The correct balanced equation is CO2 + H2 O H2 CO3. Carbondioxide reacts with water to give carbonic acid.
4. Consider the following reaction, in the presence of light
2H2 O + 2X O2 + 2XH2
Which of the following statements is true?
a) X is electron-accepting specie
b) X is electron-donating specie
c) Water is an electron acceptor
d) Water neither donates nor accepts any electron
Explanation: In this oxidation reduction sequence, water serves as the electron donor and X serves as an electron acceptor.
5. Hydrolysis reactions are catalyzed by enzymes called
Explanation: Hydrolases, which catalyze hydrolysis reaction involve in food decomposition and in digestion process.
6. What does it mean when we say that water acts as a “heat buffer”?
a) It keeps the temperature of an organism relatively constant as the temperature of the surroundings fluctuates.
b) It increases the temperature of an organism as the temperature of the surroundings increases
c) It decreases the temperature of an organism as the temperature of the surroundings increases
d) It increases the temperature of an organism as the temperature of the surroundings decreases
Explanation: Water has a high specific heat capacity, it is hard to increase or decrease the water temperature which requires a lot of heat energy and therefore water acts as a heat buffer.
7. Which of the following does not react with water?
Explanation: Be is the only alkaline earth metal which does not react with water.
8. What trend does the reactivity of group II elements follow with water?
a) Increases down the group
b) Decreases down the group
c) Does not follow any particular trend
d) No reaction
Explanation: As we descend down the group, losing of electrons from the outer orbit of an atom becomes easy.
9. Which among the following statements is true about the following chemical reaction?
3Fe(s) + 4H2 O → Fe3 O4 (s) + 4H2
a) Iron metal is getting reduced.
b) Water is acting as a reducing agent
c) Water is acting as an oxidizing agent
d) Water is getting oxidized
Explanation: Water is getting reduced and it oxidizes iron metal, thus acting as an oxidizing agent.
10. Identify the products formed in the following reaction
CH3 COOCH3 + H2 O → A + B
a) CH3 COOH and CH3 OH
b) CH3 COOOH and CH4
c) CO2 and C2 H6
d) No reaction
Explanation: Ester Hydrolysis
CH3 COOCH3 + H2 O → CH3 COOH + CH3 OH.
Sanfoundry Global Education & Learning Series – Biochemistry.
To practice all areas of Biochemistry, here is complete set of 1000+ Multiple Choice Questions and Answers.