Well B and C can be automatically dismissed. It is obviously not those.
As for A, science is not a method of inquiry.
So it has to be D.
If I was right leave a rating and a thanks!
Answer:
As2O3 → H3AsO4
As2O3 → 2H3AsO4 balance As
5H2O + As2O3 → 2H3AsO4 balance O by adding H2O to one side
5H2O + As2O3 → 2H3AsO4 + 4H+ balance H by adding H+ to one side
5H2O + As2O3 → 2H3AsO4 + 4 H+ + 4e- balance charge by adding electrons to one side
Now do the same for the other part of the reaction
NO3- → NO
NO3- → NO + 2H2O
4H+ + NO3- → NO + 2H2O
3e- + 4H+ + NO3- → NO + 2H2O
Now cancel the electrons by multiplying the first equation by 3 and the second equation by 4, then add them together
.
3As2O3 + 4NO3- + 7H2O + 4H+ → 6H3AsO4 + 4NO
Answer : The normal boiling point of ethanol will be,
or 
Explanation :
The Clausius- Clapeyron equation is :

where,
= vapor pressure of ethanol at
= 98.5 mmHg
= vapor pressure of ethanol at normal boiling point = 1 atm = 760 mmHg
= temperature of ethanol = 
= normal boiling point of ethanol = ?
= heat of vaporization = 39.3 kJ/mole = 39300 J/mole
R = universal constant = 8.314 J/K.mole
Now put all the given values in the above formula, we get:


Hence, the normal boiling point of ethanol will be,
or 