Question

What is the pH of a 0.00001 molar HCl solution? a. 1 b. 9 c. 5 d. 4

Answer 1

Answer:

pH = -㏒[H⁺]  

= -㏒[0.00001]

= -[-5]

⇒ 5  

∴ so correct option is c

Thank you!!

Answer 2

Concept: The pH scale determines how acidic or basic water is. The range is 0 to 14, with 7 representing neutrality. Acidity is indicated by pH values below 7, whereas baseness is shown by pH values above 7. Actually, pH is a measurement of the proportion of free hydrogen and hydroxyl ions in water.

Given: 0.00001 molar HCl solution

To find: pH of a 0.00001 molar HCl solution

Solution:

To make things clearer, let's first convert 0.00001 to scientific notation.

Thus 0.00001 = $1 * 10^{-5} = 10^{-5}$

We are aware that the pH of a solution is equal to the negative logarithm of the amount of hydrogen or hydronium ions present. log [$H^{+}$] = pH

Since HCl is an acid and has a high concentration of $H^{+}$, we are informed that the solution is acidic.

The law of logarithm of the exponents states that if the base is the same as the base of the logarithm, the exponent is equal to the base, therefore if we enter the concentration into the equation above, we get

pH= - log[$10^{-5}$]. (In this instance, base= 10 and a = 10)

$log_{a} a^{n} = n$

As a result, pH= log [$10^{-5}$] = - (-5). a negative multiplied by itself is positive.

Hence, the pH of 0.00001 molar HCl solution is 5.

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