The ph of a solution prepared by mixing 50.0 ml of 0.125 m naoh and 40.0 ml of 0.125 m hno3 is

Both the acid and the base are known as strong substances which means they totally dissociate into ions in aqueous solution. Mixing the two a salt would be form which is NaNO3. The unreacted substances will be the one contributing to the pH of the solution. 

0.125M HNO3 x 0.04L = 0.005 mol HNO3
0.125M NaOH x 0.05L = 0.00625 mol NaOH

As we can see, all of the HNO3 would react with NaOH so the remaining OH from the unreacted NaOH would be responsible for the pH.

0.00625 - 0.005 / ( 0.0500L + 0.0400L ) = 0.0139 M 

pOH = -log( OH- ) 
pOH = 1.86 
pH = 14.00 - pOH 
pH = 12.14

Answer:

a. energy is absorbed in the reaction.

explanation:

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.