Henderson’s equation is pH = pKa + log([salt]/[acid]). If the acid gets half neutralized the value of pH will be:

• A) 4.3
• B) 2.15
• C) 8.60
• D) 7

To determine the pH when the acid is half neutralized, we can use Henderson’s equation: pH = pKa + log([salt]/[acid]). When the acid is half neutralized, the concentration of the salt (the conjugate base) equals the concentration of the acid. This means that the ratio [salt]/[acid] becomes 1.

Since the logarithm of 1 is 0, the equation simplifies to:

pH = pKa + log(1) = pKa + 0 = pKa

Therefore, the pH will equal the pKa of the acid. Without the specific value of pKa provided, we cannot determine the exact pH value from the options given. However, if we assume that the pKa is around 4.3 (a common value for many weak acids), then:

pH = 4.3

Thus, the correct answer is:

• A) 4.3