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

  • Lime water [Ca(OH) 2 ] is a test for Carbon Dioxide [CO 2 ]. CO 2 turns lime water milky.
  • When we exhale,  carbon dioxide gas is expelled.
  • Upon reacting with lime water, calcium carbonate is formed.
  • Calcium carbonate is insoluble in water and turns it milky .

Test for CO2 - limewater turns milky-01.jpg

So, the correct answer is (b)

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Maninder Singh

CA Maninder Singh is a Chartered Accountant for the past 14 years and a teacher from the past 18 years. He teaches Science, Economics, Accounting and English at Teachoo