A 0.22 −mol sample of a weak acid with an unknown pKa was combined with 12.0 mL of 3.20 M KOH and the resulting solution was diluted to 1.500 L. The measured pH of the solution was 3.90. What is the pka of the weak acid?

pka of the weak acid = 4.64

Explanation:

pH of solution is calculated by using Henderson - Hasselbalch equation

                       --------------------(i)

                HA  + KOH    ⇄    HK + H₂O

Initial    0.25       0.0384         0      0

Equm.   0.2116       0             0.0384

From equation (i)

answer: the rate of diffusion increases with increase in temperature.

increase in temperature, increases the molecular/particles speed (kinetic energy. diffusion means movement of particles through the material.

generally, the heavier the particle the more it interacts with the environment and more the temperature matters. so higher temperature results in higher diffusion.

c. because step up transformer steps up the input voltage i.e increases the input voltage  

the number of turns are greater on the secondary side of step up transformer  

transformer does not handle dc current