Question

What is the pH for a neutral solution at the body temperature $\left( 38{}^\circ C \right)$ ?

• A. 7.2
• B. 14
• C. 6.8
• D. 6

Answer 1

Answer: (C)

6.8

Answer 2

With the rise in temperature, the ionic-product of water increases, hence $p{{K}_{\omega }}$ decreases $\left( p{{K}_{\omega }}=\log \frac{1}{{{K}_{\omega }}} \right)$ . We know that, $pH+pOH=p{{K}_{w}}$ Hence, pH of solution also decreases with increase in temperature. Hence, at body temperature $\left( 38{}^\circ C \right)$ the pH of neutral solution will be approximately 6.8.