General Knowledge (NDA/NA SOLVED PAPER 2023) (51 to 100)

Total Questions: 50

11. Consider the following reaction:

Fe₂O₃(s) + 2Al(s) → 2Fe(s) + Al₂O₃(s)
Which of the following statements about the given reaction is NOT correct? be thog

Correct Answer: (b) It is highly endothermic reaction
Solution:The thermite reaction is an exothermic reaction not endothermic where Iron oxide reacts with Aluminum to give molten Iron and Aluminum oxide.
  • This reaction is an example of a single displacement reaction.

12. Match List I with List II and select the correct answer using the code given below the Lists:

List I (Chemical process)List II (Reaction)
A. Electrolysis of waterI. Double displacement reaction
B. Burning of coal2. Combination reaction
C. Iron nail immersed in copper sulphate solution3. Decomposition reaction
D. Addition of barium chloride solution to aluminium sulphate solution4. Displacement reaction

Code :

ABCD
(a)3421
(b)4213
(c)3241
(d)4123
Correct Answer: (c)
Solution:Electrolysis of water is a decomposition reaction. Burning of coal is a combination reaction.
Iron nail emersed in a copper sulphate solution here Iron displaces copper ions from an aqueous solution of copper sulphate. It is a single displacement reaction of one metal by another metal.
Here both Al and Ba displaces each other so it is a double displacement reaction Al₂(SO₄)₃ + BaCl₂ → AlCl₃ + BaSO₄

13. Which one of the following processes involves chemical reaction?

Correct Answer: (d) Burning of magnesium ribbon in air
Solution:In a chemical reaction, the state of the matter changes and the change is irreversible in nature from the given options (d) is correct. 2 Mg + O₂ → 2MgO + Heat
Other three are not a chemical change.

14. Which one of the following metals does NOT react with cold water to liberate hydrogen gas ?

Correct Answer: (b) Iron
Solution:Metals like Fe, Al and Zn do not react with cold as well as hot water. They only react with steam to form the metal oxide and hydrogen.

15. Consider the following reaction:

The respective state of HgO, Hg and O₂ in the above reaction is

Correct Answer: (d) Solid, liquid, gas
Solution:Mercury oxide, also called mercuric oxide or simply mercury oxide, is the inorganic compound with the formula HgO. It has a red or orange color. Mercuryoxide is a solid at room temperature and pressure. Mercury is a liquid at room temperature.
Oxygen is a gas form.

16. The two important features of sexual reproduction in higher organisms that create genetic diversity in offspring are

Correct Answer: (b) Meiosis and fertilization
Solution:Because meiosis creates cells that are destined to become gametes (or reproductive cells), this reduction in chromosome number is critical _____without it, the union of two gametes during fertilization would result in offspring with twice the normal number of chromosomes.

17. Eukaryotic cells are much more complex as compared to prokaryotes. Which one of the following structures is exclusively present in a eukaryotic cell?

Correct Answer: (d) Mitochondria
Solution:(d)

18. An important cause of tooth decay by the bacterium Streptococcus mutans is because of their ability to attach to teeth surface by producing slime layer from

Correct Answer: (a) Sugar
Solution:Streptococcus mutans, which causes tooth decay, splits the sucrose in food and uses one of the sugars to build its capsule, which sticks tightly to the tooth. The bacteria that are trapped in the capsule use the other sugar to fuel their metabolism and produce slime layer.

19. In angiosperms, pollen grain germinates to produce two male gametes. Which one of the following functions is carried out by these gametes ?

Correct Answer: (d) One gamete fuses with the egg cell and the other one fuses with a diploid secondary nucleus
Solution:(d)

20. In a sexually reproducing organism, which one of the following statements is appropriate both for the parent and offspring?

Correct Answer: (b) Both chromosome number and DNA content remains of constant Maillot
Solution:Both chromosome number and DNA content remain constant, fertilization and replication process ensure the same number of chromosome and DNA content respectively.