Class XI

 Number of electrons (e-) in phosphorus (P) is 15. valence electrons shall be
  1. 2
  2. 4
  3. 1
  4. 5
While forming soluble salts, acid is added to metal until there is no more
  1. Precipitation
  2. Polymerization
  3. H2 gas
  4. Saturation
 When hot molten liquid cools,
  1. first crystals are most pure
  2. impure substances may also form crystals
  3. it turns into gas
  4. it turns into aqueous solution
Brass is
  1. A compound
  2. A combination of copper and zinc
  3. A combination of copper and tin
  4. An alloy
 Exothermic reactions does not include
  1. Upon heating, hydrogen results in water
  2. Neutralization of acids and alkalis
  3. Respiration
  4. Breaking of chemical bond
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