The answer is
D. I and II only
Answer: False
Explanation: The density of the liquid will always be the same, no matter how much of the liquid you have.
For example, the density of the water in a pool is the same density as the water in a small cup.
Answer : The time it take to plate out will be, 3.69 minutes.
Explanation :
First we have to calculate the moles of Cr.

Molar mass of Cr = 51.9 g/mol

The cathode half-reaction is,

From this we conclude that,
The number of electrons (n) in the reaction are 3.
The quantity of charge required for the reduction of 1 mole of
= 
The quantity of charge required for the reduction of 0.0423 mole of
= 
Now we have to calculate the time taken.
We know that,


Thus, the time it take to plate out will be, 3.69 minutes.
Answer:
1.758 x 10⁻¹¹.
Explanation:
∵ pH = - log[H⁺].
∴ 5.47 = -log[H⁺].
log[H⁺] = -5.47.
∴ [H⁺] = 3.388 x 10⁻⁶ M.
∵ [H⁺] = √(Ka.C)
∴ [H⁺]² = Ka.C
<em>∴ Ka = [H⁺]²/C </em>= (3.388 x 10⁻⁶)²(0.653) = <em>1.758 x 10⁻¹¹.</em>