H2O, also known as water, stands for two hydrogen atoms and one oxygen atom. Hope this helps! ^^
The volume of H₃PO₄ : 13.33 ml
<h3>Further explanation</h3>
Given
0.003 M Phosphoric acid-H₃PO₄
40 ml of 0.00150 M Calcium hydroxide-Ca(OH)₂
Required
Volume of H₃PO₄
Solution
Acid-base titration formula
Ma. Va. na = Mb. Vb. nb
Ma, Mb = acid base concentration
Va, Vb = acid base volume
na, nb = acid base valence (amount of H⁺/OH⁻)
H₃PO₄⇒3H⁺ + PO₄³⁻ ⇒ 3 H⁺ = valence = 3
Ca(OH)₂⇒Ca²⁺ + 2OH⁻⇒ 2 OH⁻ = valence = 2
Input the value :
a = H₃PO₄, b = Ca(OH)₂
0.003 x Va x 3 = 0.0015 x 40 x 2
Va = 13.33 ml
Explanation:
It is known that the relation between pH and
is as follows.
pH = ![pK_{a} + log \frac{[salt]}{[acid]}](https://tex.z-dn.net/?f=pK_%7Ba%7D%20%2B%20log%20%5Cfrac%7B%5Bsalt%5D%7D%7B%5Bacid%5D%7D)
and, 
Hence, first we will calculate the value of
as follows.

=
= 4.75
Now, we will calculate the value of pH as follows.
pH = ![pK_{a} + log \frac{[\text{sodium acetate}]}{\text{acetic acid}}](https://tex.z-dn.net/?f=pK_%7Ba%7D%20%2B%20log%20%5Cfrac%7B%5B%5Ctext%7Bsodium%20acetate%7D%5D%7D%7B%5Ctext%7Bacetic%20acid%7D%7D)
=
= 4.75 + (-0.677)
= 4.07
Therefore, we can conclude that the pH of given solution is 4.07.
Answer:
The mass ratio of oxygen rounded to the nearest whole no. 3 : 2
Explanation:
According to Law of Multiple proportion when two elements combine to make two or more different compounds, the mass ratio of the two element in the first compound, when divided by the mass ratio of the second compound , form a simple whole number ratio.
Compound A contains 1.34 g of sulfur for every 0.86 g of oxygen

Compound B contains 11.63 g of sulfur for every 10.49 g of oxygen

Ratio of oxygen in each compound
always put the larger number over the smaller number.
