(d) 6.023 x 1023
Ans: (d)
21. The addition of a neutron to the nucleus of an atom
    (a) increases the atomic mass of the atom
    (b) decreases the atomic mass of the atom
    (c) increases the charge on the nucleus
    (d) decreases the charge on the nucleus
Ans: (a)
22. Which of the following is a halogen?
    (a) Radon
    (b) Astatine
    (c) Cesium
    (d) Ruthenium
Ans: (b)
23. Which among the following is a metalloid?
    (a) Tin
    (b) Silver
    (c) Iodine
    (d) Arsenic
Ans: (d)
24. A non-metal which is a good conductor of electricity is
    (a) graphite
    (b) phosphorus
    (c) sulphur
    (d) iodine
Ans: (a)
25. An element which is preserved under water is
    (a) Sodium
    (b) red phosphorus
    (c) white phosphorus
    (d) sulphur
Ans: (c)
26. Quick lime has the formula
    a) CaO
    b) Ca(OH)2
    c) NaOH
    d) Na2CO3
Ans: (a)
27. "Hypo" is
    (a) sodium nitrate
    (b) Potassium nitrate
    (c) sodium thiosulphate
    (d) ammonium chloride
Ans: (c)
28. The compound used in photography is
    (a) ammonium dichromate
    (b) copper Sulphate
    (c) magnesium Sulphate
    (d) sodium thiosulphate
Ans: (d)
29. Brine is a solution of
    (a) sodium chloride in water
    (b) iodine in alcohol
    (c) sulphur in carbon disulphide
    (d) Potassium iodide in water
Ans: (a)
30. Which of the following is a Bleaching agent?
    (a) Potassium chlorate
    (b) Hydrogen peroxide
    (c) Copper sulphate
    (d) Silver Nitrate