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