Combustion Data Qns

• chocolates-xed

  14 Oct 09, 23:18

    10 cm³ of a hydrocarbon was burnt in 70 cm³ of oxygen (an excess) at 425K. After cooling to room temperature, the gaseous mixture volume decreased from 90 cm³ to 50 cm³. A further reduction of 30 cm³ was observed when the residual gas was passed through calcium hydroxide. (All gas volumes are at the same temperature and pressure).

   What is the empirical formula of the hydrocarbon?

               A         C₃H₆

              B         C₃H₈

              C         C₄H₈

              D         C₄H₁₀

   

  in this qn right... we must use the Combustion formula... but how to use the information of reduction of 30cm3 in the residual gas??

• UltimaOnline

  15 Oct 09, 00:05

  ~ but how to use the information of reduction of 30cm3 in the residual gas?? ~ CO2 is an acidic gas, it is hydrolysed and neutralized by alkalis.
• dkcx

  15 Oct 09, 00:09

  Isn't Ca(OH)2 very commonly use to test CO2 that even primary schools kids learn though they call it lime water?