Standard Gibb’s free energy change for isomerization reaction $$cis{\text{ - }}2{\text{ - pentene}} \rightleftharpoons trans{\text{ - }}2{\text{ - pentene}}$$        is $$ - 3.67\,kJ/mol$$   at $$400\,K.$$  If more $$trans{\text{ - }}2{\text{ - pentene}}$$     is added to the reaction vessel, then

Solution :
If more $$trans{\text{ - }}2{\text{ - pentene}}$$    is added, then its concentration in right hand side will increase. But in order to maintain the $$K$$ constant, concentration of $$cis{\text{ - }}2{\text{ - pentene}}$$    will also increase. Therefore more $$cis{\text{ - }}2{\text{ - pentene}}$$    will be formed.