question_answer 45)

    When air is blown from mouth into a test-tube containing lime water, the lime water turned milky due to the presence of (a) oxygen                          (b) carbon dioxide           (c) nitrogen                        (d) water vapour

Answer:

                  (b) Carbon dioxide gas turns lime water milky. When air is blown from mouth into test-tube, the lime water turned milky because the air we breathe out has more CO2.