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