Test Series

1. How many hydrogen atoms are present in a molecule of methane (CH4)?

2. Which of the following pair represents isotones?

3. Covalent bond formation between two atoms takes place by

4. Which of the following bonds will be most difficult to break?

5. When a radioactive phosphorus is incorporated into DNA strand, the phosphodiester bond generally break after a short while because-

6. The solubility of NaCl is greater in water than ethanol. What physical property of the solvernt governs this difference?

7. Which molecule serves as the universal energy carrier in biological systems?

8. What is the smallest unit of an element that still retains its chemical properties?

9. How many naturally occurring elements are there in the periodic table?

10. In crystalline NaCl, how many Chloride ions surround each sodium ion?

11. Half-life of radioactive material does not depend upon

Given below are some physicochemical properties (column X) and their manifestations (column Y).
.                    X                                               Y
A. Pauling electronegativity           (i) Charge separation
B. Isolated It-orbital                       (ii) Solvation of atoms
C. Aromaticity                                (iii) Restricted rotation
D. Dielectric constant                     (iv) Planarity of molecules

12. Which one of the following is the most appropriate match?

13. Which of the following molecules is considered the building block of proteins?

14. What type of bond is formed when atoms share electrons?

15. The interaction energy between atom A and B is 400 kJ/mol-1. The type of interaction between them is

16. Which type of bond is responsible for the unique properties of water, such as surface tension and high specific heat?

17. What is the chemical formula for water?

From the following statements,
A. Hydrogen, Deuterium and Tritium differ in the number of protons
B. Hydrogen, Deuterium and Tritium differ in the number of neutrons
C. Both Deuterium and Tritium are radioactive and decay to Hydrogen and Deuterium, respectively.
D. Tritium is radioactive and decays to Helium
E. Carbon-14 decays to Nitrogen-14
F. Carbon-14 decays to Carbon-13
Pick the combination with ALL correct statements

19. Arrange them according to decreasing order of strength

20. Which of the following elements is NOT a primary component of organic molecules?

21. What would be approx. energy released on breaking H-H covalent bond?

22. How many electrons can the first energy level (or shell) of an atom hold?