Question

The ph of lemon juice is approximately 2.4. at this ph, the hydronium ion concentration is closest to which value? 1. 250 m 2. 4.00 × 10−3 m 3. 2.50 × 10−12 m 4. 5.62 × 10−4 m

Answer 1

Answer is: concentration of hydrogen cations in lemon juice is 4.00 × 10−3 m.

pH = 2.4.

pH = -log[H₃O+].

[H₃O+] = 10∧(-pH).

[H₃O+] = 10∧(-2.4).

[H₃O+] = 0.004 mol/L.

pH value (potential of hydrogen - [H+]) is a logarithmic scale that specify the acidity or basicity of an aqueous solution. When pH is greater than seven, aqueous solution is basic, below seven is acidic and when pH is equal seven, solution is neutral.

Answer 2

Answer : The correct option is, (2) $4.00\times 10^{-3}M$

Explanation:

pH : It is defined as the negative logarithm of hydrogen ion or hydronium ion concentration.

The mathematical expression is :

$pH=-\log [H^+]$

or,

$pH=-\log [H_3O^+]$

Now we have to calculate the $H_3O^+$ concentration.

$pH=-\log [H_3O^+]$

$2.4=-\log [H_3O^+]$

$[H_3O^+]=3.98\times 10^{-3}M\approx 4.00\times 10^{-3}M$

Therefore, the $H_3O^+$ concentration is, $4.00\times 10^{-3}M$