In an experiment, salt of Sodium Carbonate (Na₂CO₃) is dissolved in Water (H₂O), then NaOH and a carbonic acid is formed. This experment is an example of

Combustion of a candle is

A. physical change

B. reduction reaction

C. endothermic reaction

D. exothermic reaction

Which law of the thermochemistry introduces the concept of entropy?

A. Second Law

B. Zeroth Law

C. Third Law

D. First Law

Which of the following is a closed system?

A. Jet engine

B. Tea placed in steel kettle

C. Pressure cooker

D. Rocket engine during propulsion

The entropy of perfectly crystalline solid at absolute zero is

A. positive

B. negative

C. Zero

D. not definite