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