Chemical Reactions And Equations

3 Questions
  1. 1
    Which of the following is/are the example/examples of chemical change?
    1. Crystallization of sodium chloride
    2. Melting of ice
    3. Souring of milk
    Select the correct answer using the code given below.
    UPSC CSE I - 2014
  2. 2

    Mixture of which one of the following pairs of gases is the cause of occurrence of mast of the explosions in mines?

    UPSC CSE I - 2008
  3. 3

    Match List-I (Oxidation number) with List II (The element) and select the correct answer using the codes given below the lists:

    List-I (Oxidation number) List-II (The elements)
    A. 2 1. Oxidation number of Mn in MaO2
    B. 3 2. Oxidation number of S in H2S5O7
    C. 4 3 Oxidation number of Ca in CaO
    D. 6 4. Oxidation number of Al in NaA1H4

    Codes:
    ABCD

    UPSC CSE I - 2002