<span>physical changes
Physical changes happen when something undergoes a transformation that does not alter their total inward arrangement. This appears differently in relation to the idea of compound change in which the creation of a substance changes or at least one substances consolidate or separate to frame a new one</span>
<span>Answer:
Correct answers are- Electron affinity decreases; Cl has 7 valence electrons but Na has only 1. So Na is going to lose its e, Cl is going to gain an e.</span>
<u>Answer:</u> The volume of stock solution needed is 90 mL
<u>Explanation:</u>
To calculate the molarity of the diluted solution, we use the equation:

where,
are the molarity and volume of the stock sulfuric acid solution
are the molarity and volume of diluted sulfuric acid solution
We are given:

Putting values in above equation, we get:

Hence, the volume of stock solution needed is 90 mL