Which of the following solutions will have pH close to 1.0?

Options

A. `"100 ml" N//10HCl+"100 ml" N//10 NaOH`
B. `55 ml N/10 HCl+45ml N//10 NaOH`
C. `10 ml N//10 HCl+90ml N//10 NaOH`
D. `75ml N//5 HCl+25 ml N//5 NaOH`

Answer

4

Explanation

Only `2^(nd)` or `4^(th)` option will be acidic in nature for `2^(nd)` option.
`{:(,NaOH,+,HCl,rarr,NaCl,+,H_(2)O),("For " 2^(nd) option,,,,,,,),("initial mmol",4.5,,5.5,,0,,),("mmol after",0,,1,,4.5,,):}`
`[HCl]=(1)/(100)=10^(-2)`
`[H^(+)]=10^(-2)`
`{:(,NaOH,+,HCl,rarr,NaCl,+,H_(2)O),("For " 2^(nd) option,,,,,,,),("initial mmol",05,,15,,0,,),("mmol after",0,,10,,5,,):}`
`[HCl]=(1)/(100)=10^(-1)`
`[H^(+)]=10^(-1)`
`pH=1`
Hence `(4)`.