The specific heat capacities of two substances are given in the table below.

Which statement is correct?

A.     More heat is needed to increase the temperature of 50 g of water by 50 °C than 50 g of ethanol by 50 °C.

B.     If the same heat is supplied to equal masses of ethanol and water, the temperature of the water increases more.

C.     If equal masses of water at 20 °C and ethanol at 50 °C are mixed, the final temperature is 35 °C .

D.     If equal masses of water and ethanol at 50 °C cool down to room temperature, ethanol liberates more heat.

The enthalpy changes of three reactions are given below.

     ${\text{2HCOOH(l)}} + {{\text{O}}_2}{\text{(g)}} \to {\text{2C}}{{\text{O}}_2}{\text{(g)}} + {\text{2}}{{\text{H}}_2}{\text{O(l)}}$     $\Delta H = a$

     ${{\text{C}}_2}{{\text{H}}_5}{\text{OH(l)}} + {\text{3}}{{\text{O}}_2}{\text{(g)}} \to {\text{2C}}{{\text{O}}_2}{\text{(g)}} + {\text{3}}{{\text{H}}_2}{\text{O(l)}}$     $\Delta H = b$

     ${\text{2HCOO}}{{\text{C}}_2}{{\text{H}}_5}{\text{(l)}} + {\text{7}}{{\text{O}}_2}{\text{(g)}} \to {\text{6C}}{{\text{O}}_2}{\text{(g)}} + {\text{6}}{{\text{H}}_2}{\text{O(l)}}$     $\Delta H = c$

What is the enthalpy change for the following reaction?

$${\text{HCOOH(l)}} + {{\text{C}}_2}{{\text{H}}_5}{\text{OH(l)}} \to {\text{HCOO}}{{\text{C}}_2}{{\text{H}}_5}{\text{(l)}} + {{\text{H}}_2}{\text{O(l)}}$$

A.     $a + b + c$

B.     $a + 2b - c$

C.     $\frac{1}{2}a + b + \frac{1}{2}c$

D.     $\frac{1}{2}a + b - \frac{1}{2}c$

A

D