what will be the percentage composition by mass of a solution made by dissolving 22.5 g of sodium hydroxide in 75.0 g water

We are Given:

22.5 grams of NaOH in 75 grams of H₂O

2NaOH + 2H₂O →  2Na(OH)₂ + H₂

from this equation, we can see that for 2 moles of both NaOH and H₂O, we get 2 Moles of Na(OH)₂

Calculating the number of moles of NaOH and H₂O provided:

Moles of NaOH:

molar mass of NaOH = 40 grams/mol

Given mass of NaOH = 22.5 grams

Number of moles of NaOH = Given mass / Molar mass

Number of moles of NaOH = 22.5 / 40

Number of moles of NaOH = 1.125 moles of NaOH

Moles of H₂O:

molar mass of H₂O = 18 grams / mol

given mass of H₂O = 75 grams

Number of moles of H₂O = Given mass / Molar mass

Number of moles of H₂O = 75 / 18 = 4.167 moles of H₂O

Number of Moles of NaOH and H₂O which will actually react:

from the equation, we know that the moles of NaOH and H₂O react in 1:1 ratio

So, we can say that one mole of NaOH reacts with one mole of H₂O

but we have much less NaOH than H₂O

So, only the moles equal to the number of moles of NaOH will react of either compound

1.125 moles of both NaOH and H₂O will react

Moles of Na(OH)₂ formed:

we know from the equation that the moles of NaOH and H₂O react to form  moles of Na(OH)₂ in the ratio 1:1:1

So, 1.125 moles of Na(OH)₂ will be formed

Percentage composition by mass:

amount of water present alongside the Na(OH)₂ formed:

we were given 4.167 moles of H₂O and only 1.125 moles of it was consumed in the reaction

so, 4.167 - 1.125 = 3 moles of H₂O will be present alongside the Na(OH)₂

3 moles of H₂O = 3 * 18 = 54 grams of H₂O will be present along the Na(OH)₂

Mass of Na(OH)₂ formed:

mass = number of moles * molar mass

mass = 1.125 * 41  = 46 grams of Na(OH)₂ will be formed

Total mass of the solution formed:

total mass = mass of H₂O + mass of Na(OH)₂

total mass = 54 + 46 = 100 grams

Percent composition by mass of Na(OH)₂:

Mass% of Na(OH)₂ = (Mass of Na(OH)₂ / Total mass) * 100

Mass% of Na(OH)₂ = 46 %

if two electrons have the same n, the same ℓ, and the same ml, then they are in the same orbital. the pauli exclusion principle states that no two identical fermions (a fancy word for electrons and other subatomic particles like electrons) may occupy the same quantum state in an atom simultaneously.