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Some Basic Concepts of Chemistry · Question 3

RE-NEET (UG) 2026MCQEasy📈 Topic in 25% papers+4−1
1

The numbers 17.0145 and 21.0235 were rounded to three figures after the decimal point. The resulting numbers, respectively, are

  1. 17.015 and 21.024
  2. 17.014 and 21.023
  3. 17.015 and 21.023
  4. 17.014 and 21.024

Answer

(4) 17.014 and 21.024

Solution

Rules for rounding off:

If the digit to be dropped is 5:

1. In 17.0145, the preceding digit is 4 (an even number), so it is left unchanged 17.014.

2. In 21.0235, the preceding digit is 3 (an odd number), so it is increased by 1 21.024.

Thus, the resulting numbers are 17.014 and 21.024.

Answer: (4)

RE-NEET (UG) 2026

Keep practising — Some Basic Concepts of Chemistry

2

The amount of carbon dioxide evolved upon complete combustion of 116 g of n-butane is (Given: atomic mass in amu H = 1, C = 12 and O = 16)

  1. 362 g
  2. 352 g
  3. 322 g
  4. 176 g
RE-NEET (UG) 2026
3

Among the following, choose the ones with equal number of atoms. Choose the correct answer from the options given below:

  1. B, C, and D only
  2. B, D, and E only
  3. A, B, and C only
  4. A, B, and D only
NEET (UG) 2025
4

Dalton's Atomic theory could not explain which of the following?

  1. Law of multiple proportion
  2. Law of gaseous volume
  3. Law of conservation of mass
  4. Law of constant proportion
NEET (UG) 2025
5

1 gram of sodium hydroxide was treated with 25 mL of 0.75 M HCl solution, the mass of sodium hydroxide left unreacted is equal to

  1. 750 mg
  2. 250 mg
  3. Zero mg
  4. 200 mg
NEET (UG) 2024
6

The highest number of helium atoms is in

  1. 4 mol of helium
  2. 4u of helium
  3. 4 g of helium
  4. 2.271098 L of helium at STP
NEET (UG) 2024
7

A compound X contains 32\% of A, 20\% of B and remaining percentage of C. Then, the empirical formula of X is : (Given atomic masses of A=64 ; B=40 ; C=32 u)

  1. A2BC2
  2. ABC3
  3. AB2C2
  4. ABC4
NEET (UG) 2024
8

The amount of glucose required to prepare 250 mL of M20 aqueous solution is : (Molar mass of glucose : 180 g mol-1)

  1. 2.25 g
  2. 4.5 g
  3. 0.44 g
  4. 1.125 g
RE-NEET (UG) 2024
9

1.0 g of H2 has same number of molecules as in:

  1. 14 g of N2
  2. 18 g of H2O
  3. 16 g of CO
  4. 28 g of N2
RE-NEET (UG) 2024
10

The right option for the mass of CO2 produced by heating 20 g of 20\% pure limestone is (Atomic mass of Ca = 40) [ CaCO3 1200 K CaO + CO2]

  1. 1.76 g
  2. 2.64 g
  3. 1.32 g
  4. 1.12 g
NEET (UG) 2023
11

In one molal solution that contains 0.5 mole of a solute, there is

  1. 500 mL of solvent
  2. 500 g of solvent
  3. 100 mL of solvent
  4. 1000 g of solvent
NEET (UG) 2022

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