/6 Science Quiz (for 12 to 16 years old): Quiz 18 1 / 6Which of the gas is not known as greenhouse gas? Methane Hydrogen Carbon dioxide Nitrous oxide 2 / 6Soda water contains carbonic acid sulphuric acid carbon dioxide nitrous acid 3 / 6Permanent hardness of water may be removed by the addition of lime potassium permanganate sodium carbonate alum 4 / 6The hardest substance available on earth is Platinum Gold Iron Diamond 5 / 6Potassium nitrate is used in fertiliser glass medicine salt 6 / 6Bromine is a black solid red liquid colourless gas highly inflammable gas Your score is 0% Restart quiz Next quiz Please rate the quiz Send feedback By WordPress Quiz plugin