P-BLOCK GROUP 13 & 14 — 50 MCQs

JEE + NEET Practice

GROUP 13 — BORON FAMILY

1. The general electronic configuration of Group 13 elements is:

A) $ns^2np^1$
B) $ns^2np^2$
C) $ns^1np^2$
D) $ns^2np^3$

2. Which element of Group 13 shows the maximum covalent character?

A) B
B) Al
C) Ga
D) Tl

3. The most important reason for the anomalous behaviour of boron is:

A) Large size
B) Low ionisation enthalpy
C) Small size and high ionisation enthalpy
D) Metallic character

4. Which Group 13 element is a metalloid?

A) B
B) Al
C) Ga
D) Tl

5. The correct order of atomic radii in Group 13 is:

A) B < Al < Ga < In < Tl
B) B < Ga < Al < In < Tl
C) B < Al < In < Ga < Tl
D) Al < B < Ga < In < Tl

6. Which element exhibits the maximum tendency for the +1 oxidation state?

A) B
B) Al
C) Ga
D) Tl

7. The inert pair effect is maximum in:

A) B
B) Al
C) Ga
D) Tl

8. Which of the following is electron deficient?

A) $NH_3$
B) $BF_3$
C) $CH_4$
D) $H_2O$

9. The hybridisation of boron in $BF_3$ is:

A) $sp$
B) $sp^2$
C) $sp^3$
D) $dsp^2$

10. $BF_3$ acts as:

A) Lewis acid
B) Lewis base
C) Brønsted acid only
D) Oxidising agent only

11. The shape of $BF_3$ is:

A) Linear
B) Trigonal planar
C) Tetrahedral
D) Pyramidal

12. Which is the strongest Lewis acid?

A) $BF_3$
B) $BCl_3$
C) $BBr_3$
D) $BI_3$

13. The Lewis acidity of boron trihalides follows:

A) $BF_3>BCl_3>BBr_3>BI_3$
B) $BF_3<BCl_3<BBr_3<BI_3$
C) $BF_3=BCl_3=BBr_3=BI_3$
D) $BCl_3>BF_3>BBr_3>BI_3$

14. The unusual Lewis acidity order of boron halides is mainly due to:

A) Electronegativity only
B) Back bonding
C) Hydrogen bonding
D) Steric effect only

15. Borax has the formula:

A) $NaBO_2$
B) $Na_2B_4O_7\cdot10H_2O$
C) $H_3BO_3$
D) $Na_3BO_3$

16. Boric acid is:

A) Tribasic
B) Dibasic
C) Monobasic
D) Strong acid

17. Boric acid behaves as a Lewis acid because it:

A) Donates $H^+$ directly
B) Accepts $OH^-$
C) Donates $OH^-$
D) Accepts $H^+$

18. On heating boric acid, the final product formed is:

A) $B_2O_3$
B) $B_2O_5$
C) $BO_2$
D) $B_2O$

19. Aluminium reacts with NaOH to form:

A) $AlCl_3$
B) Sodium aluminate
C) $Al_2O_3$ only
D) $Al(OH)_3$ only

20. Which oxide is amphoteric?

A) $B_2O_3$
B) $Al_2O_3$
C) $CO_2$
D) $SO_2$

21. Aluminium becomes passive in concentrated $HNO_3$ because:

A) Al dissolves rapidly
B) A protective oxide layer forms
C) Aluminium nitrate evaporates
D) Hydrogen is evolved

22. Cryolite used in the extraction of aluminium is:

A) $AlF_3$
B) $Na_3AlF_6$
C) $NaAlO_2$
D) $Al_2O_3$

23. The main purpose of cryolite in the Hall-Héroult process is to:

A) Increase melting point
B) Lower melting point and increase conductivity
C) Act as reducing agent
D) Produce aluminium chloride

24. Which of the following is NOT a property of boron?

A) It is a metalloid
B) It forms electron-deficient compounds
C) It readily forms $B^{3+}$ ions in aqueous solution
D) It forms covalent compounds

25. Diborane has the molecular formula:

A) $BH_3$
B) $B_2H_6$
C) $B_2H_4$
D) $BH_4$

---

GROUP 14 — CARBON FAMILY

26. General electronic configuration of Group 14 elements is:

A) $ns^2np^1$
B) $ns^2np^2$
C) $ns^2np^3$
D) $ns^1np^3$

27. Which element shows the maximum catenation?

A) C
B) Si
C) Ge
D) Sn

28. The exceptional catenation ability of carbon is mainly due to:

A) Large size
B) Strong C–C bond
C) Metallic character
D) Low ionisation enthalpy

29. The most stable oxidation state of carbon is:

A) +4 only
B) +2 only
C) −4 only
D) Depends on compound

30. Down Group 14, the stability of +2 oxidation state:

A) Decreases
B) Increases
C) Remains constant
D) First increases then decreases

31. The inert pair effect in Group 14 is maximum for:

A) C
B) Si
C) Sn
D) Pb

32. Which compound is a greenhouse gas?

A) CO₂
B) CO
C) SiC
D) $CH_4$

33. Carbon monoxide is:

A) Strongly acidic oxide
B) Neutral oxide
C) Strongly basic oxide
D) Amphoteric oxide

34. Carbon dioxide is:

A) Basic oxide
B) Acidic oxide
C) Neutral oxide
D) Amphoteric oxide

35. Which of the following is an allotrope of carbon?

A) Quartz
B) Graphite
C) Silica
D) Silicate

36. In diamond, each carbon atom is:

A) $sp$-hybridised
B) $sp^2$-hybridised
C) $sp^3$-hybridised
D) $dsp^2$-hybridised

37. In graphite, each carbon atom is:

A) $sp$-hybridised
B) $sp^2$-hybridised
C) $sp^3$-hybridised
D) $sp^3d$-hybridised

38. Graphite conducts electricity because:

A) It contains ionic bonds
B) It has delocalised electrons
C) Carbon is metallic
D) It contains free protons

39. Which allotrope of carbon is the hardest naturally occurring substance?

A) Graphite
B) Diamond
C) Fullerene
D) Graphene

40. Silicon dioxide has:

A) Linear molecular structure
B) Tetrahedral 3-D network structure
C) Ionic structure
D) Planar molecular structure

41. The basic structural unit of $SiO_2$ is:

A) $SiO_6$ octahedron
B) $SiO_4$ tetrahedron
C) $SiO_3$ triangle
D) $SiO_2$ molecule

42. Which oxide is acidic?

A) $CO$
B) $CO_2$
C) $SnO$
D) PbO

43. Which Group 14 element has the strongest tendency to form $+2$ oxidation state?

A) C
B) Si
C) Sn
D) Pb

44. The reaction of $CO_2$ with lime water initially gives:

A) $CaCO_3$
B) $Ca(HCO_3)_2$
C) $CaO$
D) $Ca(OH)_2$

45. On passing excess $CO_2$ through lime water, the solution becomes clear because:

A) $CaCO_3$ converts into soluble $Ca(HCO_3)_2$
B) $CaCO_3$ decomposes to CaO
C) $CO_2$ escapes
D) CaO precipitates

46. Which of the following is used as a semiconductor?

A) Diamond
B) Silicon
C) Graphite
D) CO₂

47. Silicon reacts with nitrogen at high temperature to form:

A) $SiN$
B) $Si_3N_4$
C) $Si_2N_3$
D) $SiN_2$

48. Which of the following is a carbide?

A) $SiC$
B) $SiO_2$
C) $SiCl_4$
D) $SiH_4$

49. Silicones are polymers containing repeating:

A) C–C–C chain only
B) Si–O–Si linkage
C) Si–Si–Si linkage only
D) C–O–C linkage only

50. Which statement is correct?

A) CO₂ is linear and non-polar
B) CO₂ is bent and polar
C) SiO₂ is a discrete linear molecule
D) Diamond conducts electricity efficiently

Answer Key

Q	Ans	Q	Ans	Q	Ans	Q	Ans	Q	Ans
1	A	11	B	21	B	31	D	41	B
2	A	12	A	22	B	32	A	42	B
3	C	13	C	23	B	33	B	43	D
4	A	14	B	24	C	34	B	44	A
5	B	15	B	25	B	35	B	45	A
6	D	16	C	26	B	36	C	46	B
7	D	17	B	27	A	37	B	47	B
8	B	18	A	28	B	38	B	48	A
9	B	19	B	29	D	39	B	49	B
10	A	20	B	30	B	40	B	50	A