sir..here how does value 2.303 came while solving numerical???

sir..here how to calculate value of log(273/263) without using calculator??

Here sir had directly said the answer but took alot of time without using calculator to me..please sir..how can i calculate quickly..is there any tirick for calculation??

sir why the work done in an isobaric process is the maximum?

I'm not able to understand why sodium and chloride ion would not bind together