4.48
pH=pKa+log([A-/HA])
25% deprotonated tells us that A- is .25 and that the rest (75% is protonated) thats .75.
4 = pKa + log

4 - log

= pKa
4.48=pKa
10g/ 763g/mol= 0.013moles
your answer is c hope this helps
<span>it tells you the sequence in which events occurred, not how long ago they occurred.</span>
Your answer to your question is: 1s² 2s² 2p⁶