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