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p-Block Elements (Group 13 & 14) · Question 4

JEE Main 2026 (Online) 28th January Evening ShiftMCQMedium📈 Topic in 32% papers+4−1
1

Consider the following reactions Na2B4O7 2X + Y CuSO4 + Y Non-luminous flame Z + SO3 2Z + 2X + Carbon Luminous flame 2Q + Na2B4O7 + CO The oxidation states of Cu in Z and Q, respectively are :

  1. +2 and +1
  2. +1 and +1
  3. +1 and +2
  4. +2 and +2

Answer

(1) +2 and +1

Solution

Borax bead test:

Na2B4O7 2NaBO2 + B2O3 X = NaBO2, Y = B2O3

Oxidising (non-luminous) flame: CuSO4 + B2O3 Cu(BO2)2 + SO3

Z = Cu(BO2)2 (blue cupric metaborate): x + 2(−1) = 0 Cu = +2

Reducing (luminous) flame: 2Cu(BO2)2 + 2NaBO2 + C 2CuBO2 + Na2B4O7 + CO

Q = CuBO2 (colourless cuprous metaborate): x + (−1) = 0 Cu = +1

Answer: (1)

JEE Main 2026 (Online) 28th January Evening Shift

Keep practising — p-Block Elements (Group 13 & 14)

2

Choose the INCORRECT statement

  1. Carbon exhibits negative oxidation states along with +4 and +2.
  2. Carbon cannot exceed its covalency more than four.
  3. Among the isotopes of carbon, 13C is a radioactive isotope.
  4. CO2 is the most acidic oxide among the dioxides of group 14 elements.
JEE Main 2026 (Online) 24th January Evening Shift
3

The correct statements from the following are : Choose the correct answer from the options given below :

  1. B and D Only
  2. C and D Only
  3. A and D Only
  4. A and C Only
JEE Main 2026 (Online) 23rd January Morning Shift
4

It is noticed that Pb2+ is more stable than Pb4+ but Sn2+ is less stable than Sn4+. Observe the following reactions. PbO2 + Pb 2PbO; rG (1) SnO2 + Sn 2SnO; rG (2) Identify the correct set from the following

  1. rG (1) > 0; rG (2) < 0
  2. rG (1) < 0; rG (2) > 0
  3. rG (1) < 0; rG (2) < 0
  4. rG (1) > 0; rG (2) > 0
JEE Main 2026 (Online) 23rd January Evening Shift
5

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :

  1. Both Statement I and Statement II are false
  2. Statement I is false but Statement II is true
  3. Both Statement I and Statement II are true
  4. Statement I is true but Statement II is false
JEE Main 2026 (Online) 21st January Morning Shift
6

The group 14 elements A and B have the first ionisation enthalpy values of 708 and 715 kJ mol-1 respectively. The above values are lowest among their group members. The nature of their ions A2+ and B4+ respectively is

  1. both reducing
  2. oxidising and reducing
  3. both oxidising
  4. reducing and oxidising
JEE Main 2025 (Online) 7th April Morning Shift
7

The correct statements from the following are : Choose the correct answer from the options given below :

  1. A, B, D and E only
  2. A, C and D only
  3. A, B, C and E
  4. B, D and E only
JEE Main 2025 (Online) 7th April Evening Shift
8

Given below are the pairs of group 13 elements showing their relation in terms of atomic radius. (B < Al), (Al < Ga), (Ga < In) and (In < Tl). Identify the elements present in the incorrect pair and in that pair find out the element (X) that has higher ionic radius (M3+) than the other one. The atomic number of the element (X) is

  1. 49
  2. 81
  3. 31
  4. 13
JEE Main 2025 (Online) 4th April Morning Shift
9

Given below are two statements : In the light of the above statements, choose the most appropriate answer from the options given below :

  1. Statement I is correct but Statement II is incorrect
  2. Both Statement I and Statement II are incorrect
  3. Statement I is incorrect but Statement II is correct
  4. Both Statement I and Statement II are correct
JEE Main 2025 (Online) 4th April Evening Shift
10

The elements of Group 13 with highest and lowest first ionisation enthalpies are respectively :

  1. B & Tl
  2. Tl & B
  3. B & In
  4. B & Ga
JEE Main 2025 (Online) 4th April Evening Shift
11

The correct orders among the following are Choose the correct answer from the options given below:

  1. B and D Only
  2. A and B Only
  3. C and D Only
  4. A and C Only
JEE Main 2025 (Online) 3rd April Evening Shift

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