Chemistry Set 15 FAQs

1. On mixing with water, Plaster of Paris changes to:

2. India's first pharmaceutical company was established by Acharya P.C. Ray in the year:

3. The sodium compound used for removing permanent hardness of water is:

4. The number of water molecules of crystallisation in one formula unit of hydrated copper sulphate is:

5. According to the Law of Octaves, when elements are arranged in increasing order of atomic weights, similar properties recur in every:

6. The coating formed by corrosion of silver is:

7. Phosphorus is stored in:

8. When muddy water is filtered through filter paper, the mud left on the paper is called:

9. In the electrolysis of molten sodium chloride, sodium is deposited at the:

10. Winnowing separates the components of a mixture on the basis of difference in:

11. The notation used for an aqueous solution in a chemical equation is:

12. Consider the following statements: (I) The formula of the oxide of gallium is Ga₂O₃. (II) The formula of the oxide of germanium is GeO₂. (III) The formula of the chloride of gallium is GaCl₄. Which of the above is/are correct?

13. The mass of hydrogen obtained on decomposing 27 g of purified water is:

14. A magnesium atom (atomic number 12) loses two electrons to form Mg²⁺. The number of electrons in Mg²⁺ is:

15. Esters are generally:

16. The number of electrons an oxygen atom requires to complete its octet is:

17. Which of the following is a water-in-oil emulsion?

18. One reason carbon forms strong bonds with other elements is its:

19. Minerals from which a metal can be profitably extracted are called:

20. Anything which has mass and occupies space is called:

21. Quick lime reacts vigorously with water to produce:

22. The Avogadro constant, NA, is named in honour of:

23. Which of the following changes cannot be reversed?

24. In science, the purpose of separating a mixture is to obtain:

25. A reaction in which an element displaces another element from its compound is called a:

26. When fats and oils are oxidised, they become:

27. Sodium chloride exists as:

28. Production of light without heat in living organisms, as in fireflies, is called:

29. Consider the following pairs: (I) Fe + CuSO₄ → FeSO₄ + Cu – Displacement reaction (II) Na₂SO₄ + BaCl₂ → BaSO₄ + 2NaCl – Double displacement reaction (III) CaO + H₂O → Ca(OH)₂ – Decomposition reaction Which of the pairs given above is/are correctly matched?

30. Consider the following pairs: (I) CS₂ – Carbon disulfide (II) PCl₃ – Phosphorus trichloride (III) N₂O₅ – Dinitrogen tetroxide Which of the pairs given above is/are correctly matched?