The pH scale is a measurement system that indicates the concentration of H+ ions in a particular solution.
<h3>
Answer: 4.25 g/ml %</h3>
Explanation:
weight/volume percentage concentration = (mass in g ÷ volume) × 100
= (0.850 g ÷ 20 ml) × 100
= 4.25 g/ml %
∴ the weight/volume percentage concentration of the sucrose solution is 4.25 g/ml %.
This problem is providing us with the mass of hydrochloric acid and the volume of solution and asks for the pH of the resulting solution, which turns out to be 1.477.
<h3>pH calculations</h3>
In chemistry, one can calculate the pH of a solution by firstly obtaining its molarity as the division of the moles of solute by the liters of solution, so in this case for HCl we have:

Next, due to the fact that hydrochloric acid is a strong acid, we realize its concentration is nearly the same to the released hydrogen ions to the solution upon ionization. Thereby, the resulting pH is:

Which conserves as much decimals as significant figures in the molarity.
Learn more about pH calculations: brainly.com/question/1195974
Answer:
The answer would be Point of Reference.
In order to determine, whether an object has moved or not, a point of reference is required. The reference point is required to the measure the movement of the object, without a reference point the distance or displacement cannot be obtained. Hence, a reference point is very required to determine, whether the object has moved or not.
(Hope this helps) Sky