To standardize a hydrochloric acid solution, it was used as a titrant with a solid sample of sodium hydrogen carbonate, NaHCO3. The solid sample had a mass of 0.3967g, and 41.77 mL of acid was required to reach the equivalence point. Calculate the concentration of the standard solution.

0.113 M

Explanation:

The reaction that takes place is:

First we convert 0.3967 g of NaHCO₃ into moles, using its molar mass:

As 1 mol of NaHCO₃ reacts with 1 mol of HCl, in 41.77 mL of the HCl solution there were 4.72x10⁻³ moles of HCl.

With the calculated number of moles and the given volume we calculate the concentration of the solution:

pv=nrt

explanation:

a). in this case, dh> 0 and sd> 0. if t becomes larger, the term "-tds" will become more negative. at some point, it is possible that -dts will be more negative than the dh is positive, and the reaction will become spontaneous. this is probably the correct answer, but you should look at all of the other possibilities and make sure of that.