Chemistry questions with answers

1,620 multiple-choice questions. Open any question for its answer and explanation.

Questions asked in State PSC and UPSC prelims, by topic. Each topic also has notes to read.

1. Which one of the following is the shape of BrF₅?Asked in UPSC Geoscientist 2023
2. The number of angular and radial nodes for 4d orbital is respectivelyAsked in UPSC CAPF 2018
3. What is the order of increasing energy of the orbitals within a single energy level?Asked in WBCS Main Paper 4 2023
4. The shape of I3 tedAsked in Department Recruitment 2024 (Chemist) 2024
5. The total number of nodal planes in dxy orbital is - - Question not attemptedAsked in Department Recruitment 2024 (Chemist) 2024
6. Which of the following elements have half- filled f-orbitals in their ground state? (Given: atomic number, Sm = 62, Eu = 63, Tb = 65, Gd = 64, Pm = 61) - (A) Sm - (B) Eu - (C) Tb - (D) Gd - (E) Pm Choose the correct answer from the options given below - - (5) Question not attemptedAsked in Department Recruitment 2024 (Chemist) 2024
7. The number of significant figures in $6.02 \times 10^{23}$ isAsked in ae 2024
8. A pi-bond is formed by the overlap ofAsked in mineral dev officier 2025
9. Which transitions are studied by UV spectrometer?Asked in WBCS Main Paper 4 2023
10. For an element with atomic number 35, which one of the following will be the correct number of electrons in its valence shell based on Bohr's model of an atom?Asked in UPSC NDA 1 2022
11. Which one of the following statements is correct ?Asked in UPSC NDA 2 2016
12. The number of maximum electrons in N Shell isAsked in UPSC NDA 2 2020
13. What is the maximum number of electrons in the M-Shell ?Asked in UPSC NDA 2 2021
14. What is the maximum number of electrons that can occupy the first shell of an atom ?Asked in UPSC NDA 2 2024
15. How many atoms are there in one mole atom of an element?Asked in WBCS Main Paper 4 2021
16. Law of definite proportion is obeyed inAsked in WBCS Main Paper 4 2023
17. Which structure has delocalized $\pi$ electrons?Asked in WBCS Main Paper 4 2023
18. Which of the following does not have coordinate bond?Asked in WBCS Main Paper 4 2019
19. In NO3 lone pairs of electrons on Nitrogen atom are, respectively – (1) 1, 3 (2) 2, 2 (3) 3, 1 (4) 4, 0 (5) Question not attemptedAsked in Department Recruitment 2024 (Chemist) 2024
20. The number of elements in 5th period of the periodic table will be - (1) 32 (2) 8 (3) 10 (4) 18 (5) Question not attemptedAsked in Department Recruitment 2024 (Chemist) 2024
21. The chemical behavior of an atom is mostly determined by itsAsked in ASO 2025
22. The chemical properties of an element depend uponAsked in UPSC CDS 1 2017
23. What is the number of moles of 'He' in 104 g of helium gas ?Asked in UPSC CDS 1 2022
24. The correct order of atomic radius of Li, Na, Be and O isAsked in UPSC CDS 1 2024
25. How many hydrogen atoms are contained in 1.50 g of glucose (C₆H₁₂O₆)?Asked in UPSC CDS 2 2017