<h2>Solutions:</h2>
<u>Case a:</u> Finding pH for [H⁺] = 1.75 × 10⁻⁵ mol/L :
As we know pH is given as,
pH = -log [H⁺]
Putting value,
pH = -log [1.75 x 10⁻⁵]
pH = 4.75
<u>Case b:</u> Finding pH for [H⁺] = 6.50 × 10⁻¹⁰ mol/L :
As we know pH is given as,
pH = -log [H⁺]
Putting value,
pH = -log [6.50 × 10⁻¹⁰]
pH = 9.18
<u>Case c:</u> Finding pH for [H⁺] = 1.0 × 10⁻⁴ mol/L :
As we know pH is given as,
pH = -log [H⁺]
Putting value,
pH = -log [1.0 × 10⁻⁴]
pH = 4
<u>Case d:</u> Finding pH for [H⁺] = 1.50 × 10⁻⁵ mol/L :
As we know pH is given as,
pH = -log [H⁺]
Putting value,
pH = -log [1.50 × 10⁻⁵]
pH = 4.82
Answer: The freezing point of 3.46 gram of a compound X in 160 gram of benzene is 
Explanation:
The relation of density and molar mass is:

where
d = density = 3.27 g/ L
P = pressure of the gas = 773 torr = 1.02 atm (760 torr = 1atm)
M = molar mass of the gas = ?
T = temperature of the gas = 
R = gas constant = 

The relation of depression in freezing point with molality:

= depression in freezing point =
= 
= freezing point constant = 5.1
m = molality = 


Thus the freezing point of 3.46 gram of a compound X in 160 gram of benzene is 
5.5 grams of reactants. According to the Law of Conservation of Mass, mass isn’t created or lost through any chemical changes, so the total mass should remain constant from the initial reactants to the final products.
Generally speaking the larger, more massive elements are less stable, like isotopes of elements. With this said, they are less likely to react since they will become heavy and unstable. This is why chlorine is more reactive with other elements like sodium than astatine.