Which of the following compounds is electron-deficient? MCQ with Answer and Explanation

Which of the following compounds is electron-deficient?
A. H₂O
B. CH₄
C. BF₃
D. NH₃
Answer: Option C
Solution (By JKSSB Mock Tests)
In BF₃, boron has 3 valence electrons and forms 3 covalent bonds with fluorine, resulting in only 6 electrons in its valence shell. It does not complete its octet, making it an electron-deficient molecule and a strong Lewis acid. NH₃, H₂O, and CH₄ all have complete octets.

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Practice More chemistry Questions

Question #1
The atomic radius of chlorine is smaller than that of sulfur because:
A. Chlorine has greater nuclear charge pulling electrons closer
B. Sulfur has a complete octet
C. Chlorine has more shells
D. Chlorine has fewer electrons

Correct Answer: Option A


Explanation:
Across period 3, S (Z=16) to Cl (Z=17) nuclear charge increases, attracting electron cloud more strongly, reducing atomic radius. Number of shells is same (3).

This question belongs to: Science chemistry
Question #2
Assertion (A): Dry HCl gas does not change the color of dry litmus paper. Reason (R): Acids produce H⁺ ions only in the presence of water.
A. A is false but R is true.
B. Both A and R are true but R is NOT the correct explanation of A.
C. Both A and R are true and R is the correct explanation of A.
D. A is true but R is false.

Correct Answer: Option C


Explanation:
The acidic behavior of HCl is due to the presence of H⁺ (or H₃O⁺) ions, which are generated only when it dissolves in water. Without moisture, HCl doesn't dissociate to produce H⁺, so it doesn't change the color of dry litmus. Both statements are correct and R explains A.

This question belongs to: Science chemistry
Question #3
The number of protons in ¹⁸O is:
A. 18
B. 8
C. 10
D. 16

Correct Answer: Option B


Explanation:
Oxygen atomic number is 8, thus 8 protons. Isotope ¹⁸O has 8 protons + 10 neutrons = 18 mass number.

This question belongs to: Science chemistry