The answer is c. Calorimeter
        
                    
             
        
        
        
Answer:
Neutralization 
Explanation:
When an acid react with base it form the salt and  water. The reaction is also called neutralization reaction because both neutralize each other.
In neutralization reaction equal amount of acid and base react to neutralize each other and equal amount of water and salt are formed. When pH does not reach to 7 its means there is less amount of one of reactant which is not fully neutralize.
Neutralization reactions are also used as first aid. For example when someone is dealing with HCl for cleaning purpose of toilet and get touched. It is advised to neutralize it with soap, milk or egg white.
Example:
Hydrochloric acid when react with the sodium hydroxide, a salt sodium chloride and water are formed. 
Chemical equation:
HCl + NaOH → NaCl + H₂O
Titration:
Neutralization reactions are also used to determine the concentration of solution. Titration is a quantitative technique in which acid or base is gradually added into the solution whose concentration is to be determine until the neutral point is reached.
 
        
                    
             
        
        
        
It allows electrons to flow from the anode to the cathode.
        
             
        
        
        
Explanation:
Let us assume that the given data is as follows.
         V = 3.10 L,        T = 
 = (19 + 273)K = 292 K
        P = 40 torr    (1 atm = 760 torr)
So,     P = 
              = 0.053 atm
           n = ?
According to the ideal gas equation, PV = nRT.
Putting the given values into the above equation to calculate the value of n as follows.
                  PV = nRT
    
                  0.1643 = 
                     n = 
It is known that molar mass of ethanol is 46 g/mol. Hence, calculate its mass as follows.
                No. of moles = 
 
                  
   
                     mass = 
 g
                               = 0.315 g
Thus, we can conclude that the mass of liquid ethanol is 0.315 g.