• # question_answer 51)   In an exothermic reaction, heat is evolved and system loses heat to the surroundings. For such system: (a) ${{q}_{p}}$will be negative                                                (b) ${{\Delta }_{r}}H$will be negative (c) ${{q}_{p}}$will be positive                                                  (d) ${{\Delta }_{r}}H$will be positive

(a, b) In exothermic reactions: ${{\Delta }_{r}}H$ or ${{q}_{p}}=-ve$