NEET Some Basic Concepts of Chemistry PYQ practice sheet

11 previous-year NEET Chemistry questions from Some Basic Concepts of Chemistry, newest papers first. Some Basic Concepts of Chemistry carries 17 of the Chemistry questions in NEET 2020 to 2026, so this is a good place to test yourself after revising the chapter. Marking: +4 correct, −1 wrong.

1. 1.

   RE-NEET 2026

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

   • (A)
     $17.015$ and $21.024$
   • (B)
     $17.014$ and $21.023$
   • (C)
     $17.015$ and $21.023$
   • (D)
     $17.014$ and $21.024$
2. 2.

   RE-NEET 2026

   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)

   • (A)
     $352$ g
   • (B)
     $362$ g
   • (C)
     $322$ g
   • (D)
     $176$ g
3. 3.

   NEET 2026

   The number of hydrogen atoms present in 5.4 g of urea is: (Given: molar mass of urea: $60\ \text{g mol}^{-1}$; $N_A=6.022\times10^{23}$ particles mol$^{-1}$)

   • (A)
     $1.084\times10^{23}$
   • (B)
     $2.168\times10^{22}$
   • (C)
     $1.084\times10^{22}$
   • (D)
     $2.168\times10^{23}$
4. 4.

   NEET 2026

   When $1\ \text{dm}^3$ of $\mathrm{CO_2}$ gas is passed over hot coke the volume of gaseous mixture after complete reaction at STP becomes $1.4\ \text{dm}^3$. The composition of the gaseous mixture at STP is:

   • (A)
     0.6 dm$^3$ of CO, 0.4 dm$^3$ of $\mathrm{CO_2}$
   • (B)
     0.8 dm$^3$ of CO, 0.8 dm$^3$ of $\mathrm{CO_2}$
   • (C)
     0.6 dm$^3$ of CO, 0.8 dm$^3$ of $\mathrm{CO_2}$
   • (D)
     0.8 dm$^3$ of CO, 0.6 dm$^3$ of $\mathrm{CO_2}$
5. 5.

   NEET 2024

   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

   • (A)
     200 mg
   • (B)
     750 mg
   • (C)
     Zero mg
   • (D)
     250 mg
6. 6.

   NEET 2024

   The highest number of helium atoms is in

   • (A)
     4 u of helium
   • (B)
     4 g of helium
   • (C)
     2.271098 L of helium at STP
   • (D)
     4 mol of helium
7. 7.

   NEET 2024

   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)

   • (A)
     $\mathrm{AB_2C_2}$
   • (B)
     $\mathrm{ABC_3}$
   • (C)
     $\mathrm{ABC_4}$
   • (D)
     $\mathrm{A_2BC_2}$
8. 8.

   NEET 2023

   The right option for the mass of $\mathrm{CO_2}$ produced by heating $20\ \mathrm{g}$ of $20\%$ pure limestone is (Atomic mass of Ca = 40)

   $$\mathrm{CaCO_3 \xrightarrow{1200\ K} CaO + CO_2}$$

   • (A)
     $1.32\ \mathrm{g}$
   • (B)
     $1.12\ \mathrm{g}$
   • (C)
     $1.76\ \mathrm{g}$
   • (D)
     $2.64\ \mathrm{g}$
9. 9.

   NEET 2022

   What mass of 95% pure $\mathrm{CaCO_3}$ will be required to neutralise 50 mL of 0.5 M HCl solution according to the following reaction? [Calculate upto second place of decimal point]

   $$\mathrm{CaCO_{3(s)}+2HCl_{(aq)}\rightarrow CaCl_{2(aq)}+CO_{2(g)}+2H_2O_{(l)}}$$

   • (A)
     9.50 g
   • (B)
     1.25 g
   • (C)
     1.32 g
   • (D)
     3.65 g
10. 10.

    NEET 2021

    An organic compound contains $78\%$ (by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this compound is : [Atomic wt. of C is 12, H is 1]

    • (A)
      $\mathrm{CH_2}$
    • (B)
      $\mathrm{CH_4}$
    • (C)
      $\mathrm{CH_3}$
    • (D)
      $\mathrm{CH}$
11. 11.

    NEET 2020

    Which one of the followings has maximum number of atoms?

    • (A)
      1 g of Ag(s) [Atomic mass of Ag = 108]
    • (B)
      1 g of Mg(s) [Atomic mass of Mg = 24]
    • (C)
      1 g of $\mathrm{O_2}$(g) [Atomic mass of O = 16]
    • (D)
      1 g of Li(s) [Atomic mass of Li = 7]