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Some Basic Concepts of Chemistry · Question 13

JEE Main 2026 (Online) 22nd January Morning ShiftMCQEasy📈 Topic in 42% papers+4−1
1

In the reaction, 2Al(s) + 6HCl(aq) 2Al3+(aq) + 6Cl-(aq) + 3H2(g)

  1. 12 L HCl(aq) is consumed for every 6 L H2(g) produced.
  2. 11.2 L H2(g) at STP is produced for every mole of HCl consumed.
  3. 33.6 L H2(g) is produced regardless of temperature and pressure for every mole of Al that reacts.
  4. 67.2 L H2(g) at STP is produced for every mole of Al that reacts.

Answer

(2) 11.2 L H2(g) at STP is produced for every mole of HCl consumed.

Solution

From the equation: 2 mol Al ≡ 6 mol HCl ≡ 3 mol H2

(1) HCl is in aqueous solution, not a gas, so its volume is not related to the volume of H2 by the mole ratio. Incorrect.

(2) 6 mol HCl give 3 mol H2 1 mol HCl gives 0.5 mol H2

volume at STP = 0.5 22.4 = 11.2 L. Correct.

(3) The volume of a gas depends on temperature and pressure. Incorrect.

(4) 2 mol Al give 3 mol H2 1 mol Al gives 1.5 mol H2 = 1.5 22.4 = 33.6 L at STP, not 67.2 L. Incorrect.

Answer: (2)

JEE Main 2026 (Online) 22nd January Morning Shift

Keep practising — Some Basic Concepts of Chemistry

2

At T(K), 100 g of 98\% H2SO4 (w/w) aqueous solution is mixed with 100 g of 49\% H2SO4 (w/w) aqueous solution. What is the mole fraction of H2SO4 in the resultant solution? (Given : Atomic mass H = 1 u; S = 32 u; O = 16 u). (Assume that temperature after mixing remains constant)

  1. 0.9
  2. 0.663
  3. 0.1
  4. 0.337
JEE Main 2026 (Online) 22nd January Evening Shift
3

A + 2B AB2 36.0 g of 'A' (Molar mass : 60 g mol-1) and 56.0 g of 'B' (Molar mass : 80 g mol-1) are allowed to react. Which of the following statements are correct ? Choose the correct answer from the options given below :

  1. A and C Only
  2. A and B Only
  3. C and D Only
  4. B and D Only
JEE Main 2026 (Online) 22nd January Evening Shift
4

14.0 g of calcium metal is allowed to react with excess HCl at 1.0 atm pressure and 273 K. Which of the following statements is incorrect? [Given : Molar mass in g mol-1 of Ca – 40, Cl – 35.5, H – 1]

  1. The limiting reagent is calcium metal.
  2. 33.3 g of CaCl2 is produced.
  3. 7.84 L of H2 gas is evolved.
  4. 0.35 mol of H2 gas is evolved.
JEE Main 2026 (Online) 21st January Morning Shift
5

80 mL of a hydrocarbon on mixing with 264 mL of oxygen in a closed U-tube undergoes complete combustion. The residual gases after cooling to 273 K occupy 224 mL. When the system is treated with KOH solution, the volume decreases to 64 mL. The formula of the hydrocarbon is :

  1. C2H2
  2. C2H4
  3. C4H10
  4. C2H6
JEE Main 2026 (Online) 21st January Morning Shift
6

Aqueous HCl reacts with MnO2(s) to form MnCl2(aq), Cl2(g), and H2O(l). What is the weight (in g) of Cl2 liberated when 8.7 g of MnO2(s) is reacted with excess aqueous HCl solution? (Given Molar mass in g mol-1 Mn = 55, Cl = 35.5, O = 16, H = 1)

  1. 14.2
  2. 21.3
  3. 7.1
  4. 71
JEE Main 2026 (Online) 21st January Evening Shift
7

20 mL of sodium iodide solution gave 4.74 g silver iodide when treated with excess of silver nitrate solution. The molarity of the sodium iodide solution is M. (Nearest Integer value) (Given : Na = 23, I = 127, Ag = 108, N = 14, O = 16 g mol-1)

JEE Main 2025 (Online) 8th April Evening Shift
8

Thyroxine, the hormone, has the structure given below [figure] The percentage of iodine in thyroxine is %. (nearest integer) (Given molar mass in g mol-1 C : 12, H : 1, O : 16, N : 14, I : 127)

JEE Main 2025 (Online) 7th April Morning Shift
9

Butane reacts with oxygen to produce carbon dioxide and water following the equation given below. C4H10(g) + 132O2(g) 4CO2(g) + 5H2O(l) If 174.0 kg of butane is mixed with 320.0 kg of O2, the volume of water formed in liters is . (Nearest integer) [Given : (a) Molar mass of C, H, O are 12, 1, 16 g mol-1 respectively, (b) Density of water = 1 g mL-1]

JEE Main 2025 (Online) 7th April Evening Shift
10

Fortification of food with iron is done using FeSO4 7H2O. The mass in grams of the FeSO4 7H2O required to achieve 12 ppm of iron in 150 kg of wheat is (Nearest integer) [Given: Molar mass of Fe, S and O respectively are 56, 32 and 16 g mol-1]

JEE Main 2025 (Online) 4th April Morning Shift
11

The amount of calcium oxide produced on heating 150 kg limestone (75% pure) is kg. (Nearest integer) Given: Molar mass (in g mol-1) of Ca-40, O-16, C-12

JEE Main 2025 (Online) 4th April Evening Shift

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