<u>Answer:</u> The density of NaCl solution is 3.930 g/mL
<u>Explanation:</u>
We are given:
Mass of cylinder,
= 21.577 g
Mass of NaCl and cylinder combined, M = 39.664 g
Mass of NaCl,
= 
To calculate density of a substance, we use the equation:

We are given:
Mass of NaCl = 18.087 g
Volume of NaCl solution = 4.602 mL
Putting values in above equation, we get:

Hence, the density of NaCl solution is 3.930 g/mL
Answer:
1 gram of H2 will be produced from 12 grams of Mg.
Explanation:
According to Stoichiometry, 0.5 moles of Mg are present. 1 mole of Mg produces 1 mole of H2, so 0.5 moles of Mg will produce 0.5 moles of H2. Multiplying molar mass of H2 i.e. 2 gram/mole with 0.5 moles, we can find the mass of H2 in grams which is 1 gram.
In the given above, we have two densities which are 0.89 g/mL and 0.72 g/mL. We are also given that the liquids are immiscible. After the settlement of the liquids, they will form two layers.
The heavier substance, the one which has a higher density will be at the bottom and the lighter substance, the one which has a lower density will be at the top layer.
Answer: hydrogen
Explanation: hydrogen gas is a major component of water which occupies a large portion of the Earth's atmosphere
C6H5 is the molecular formula for Phenyl.