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