Two organic compounds A and B both containing C and H yield on analysis, the same percentage composition by weight, C =(12/13) × 100 ; H =(1/13) × 100 Which among the following will be the correct formula of the compounds ' A ' and ' B '? (' A ' decolourises bromine water but ' B ' does not.)

Question

Two organic compounds A and B both containing C and H yield on analysis, the same percentage composition by weight, C =(12/13) × 100 ; H =(1/13) × 100 Which among the following will be the correct formula of the compounds ' A ' and ' B '? (' A ' decolourises bromine water but ' B ' does not.) (A) A= C 2 H 2, B= C 6 H 6 (B) A= C 6 H 6, B= C 2 H 2 (C) A= C 2 H 4, B= C 2 H 6 (D) A= C 2 H 4, B= C 3 H 8

Tardigrade Admin · Accepted Answer

Element	Percentage	At. Mass	Relative Number of Atoms	Simplest Ratio
C	$\frac{12}{13} \times 100 = 92.30$	12	$\frac{92.30}{12} = 7.69$	1
H	$\frac{1}{13} \times 100 = 7.69$	1	$\frac{7.69}{1} = 7.69$	1

Thus, empirical formula

= C H

The two compounds which satisfy this empirical formula are

C_{2} H_{2}

and

C_{6} H_{6}

As '

A

' decolourises bromine water thus '

A

' should be

C_{2} H_{2}

and '

B

' does not decolourise bromine water thus '

B

' should be

C_{6} H_{6}

$A = C_{2} H_{2}, B = C_{6} H_{6}$

$A = C_{6} H_{6}, B = C_{2} H_{2}$

$A = C_{2} H_{4}, B = C_{2} H_{6}$

$A = C_{2} H_{4}, B = C_{3} H_{8}$

Q. Two organic compounds A and B both containing C and H yield on analysis, the same percentage composition by weight, C=1312​×100;H=131​×100 Which among the following will be the correct formula of the compounds ' A ' and ' B '? (' A ' decolourises bromine water but ' B ' does not.)

A=C2​H2​,B=C6​H6​

A=C6​H6​,B=C2​H2​

A=C2​H4​,B=C2​H6​

A=C2​H4​,B=C3​H8​

$A = C_{2} H_{2}, B = C_{6} H_{6}$

$A = C_{6} H_{6}, B = C_{2} H_{2}$

$A = C_{2} H_{4}, B = C_{2} H_{6}$

$A = C_{2} H_{4}, B = C_{3} H_{8}$