Question

When $750mL$ of $0.5MHCl$ is mixed with $250mL$ of $2MNaOH$ solution, the value of $pH$ will be:

• A. $pH=7$
• B. $pH>7$
• C. $pH<7$
• D. $pH=0$

Answer 1

Answer: (B)

$pH>7$

$n_{HCl}=M_{HCl}\times V_{HCl}$ and

$n_{NaOH}=M_{NaOH}\times V_{NaOH}$

where $n=$ number of moles

$M=molarity,V=volume$

$\therefore n_{HCl}=0.5\times 750=375milimoles$.

$n_{NaOH}=2.0\times 250=500milimoles$.

$\because n_{NaOH}>n_{HCl}$

The solution is basic and has $pH>7$.