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