Question

aMnO2 + bHCl  cMnCl2 + dH2O + eCl2
pC2H5OH + qO2  rCO2 + sH2O
a, c, q and r in the above chemical equations
respectively are
(1) 2, 4, 2 and 1 (2) 1, 1, 3 and 2
(3) 4, 2, 2 and 1 (4) 2, 1, 4 and 2

Answer 1

MnO2 + 4HCl--->MnCl2 + Cl2 +2H2O

C2H5OH + 3O2--->2CO2 + 3H2O

Completely balanced equations. So the ans is (2)

Answer 2

answer : option (2)

explanation : $aMnO_2+bHCl\Leftrightarrow cMnCl_2+dH_2O+eCl_2$

here you can see Mn is reduced and Cl is oxidised .

so, $MnO_2+4H^++2e^-\leftrightarrow Mn^{2+}+2H_2O$.....(2)

and $2Cl^-\Leftrightarrow Cl_2+2e^-$......(2)

adding equations (1) and (2)

$MnO_2+4H^++2Cl^-\Leftrightarrow Mn^{2+}+2H_2O+Cl_2$
or, $MnO_2+4HCl\Leftrightarrow MnCl_2+2H_2O+Cl_2$

hence, a = 1, b = 4, c = 1 , d = 2, e = 1

well there is no require to solve other one because answer must be option (2)

but for understanding we will solve ..

$pC_2H_5OH+qO_2\rightarrow rCO_2+sH_2O$

now, reaction will be..

$C_2H_5OH+3O_2\rightarrow 2CO_2+3H_2O$

so, p = 1, q = 3, r = 2 and s = 3

therefore ; a , c , q , r in the above chemical equation respectively are 1, 1, 3, 2 .