I think that you didn't copy the answers correctly, because 1 and 2 are the same, and 3 and 4 are also the same here.
Anyways, the answer which is correct is that an electron has a charge of -1, and a proton has a charge of +1.
Electrons are negatively charged, whereas protons are positively charged. Neutrons are neutral.
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
It is B, and also for a moment I didn't understand that 4.69 x 10^22. I almost did this whole problem wrong.
Answer : The pressure of hydrogen gas is, 739.3 torr
Explanation :
As we are given:
Vapor pressure of water = 18.7 torr
Barometric pressure = 758 torr
Now we have to calculate the pressure of hydrogen gas.
Pressure of hydrogen gas = Barometric pressure - Vapor pressure of water
Pressure of hydrogen gas = 758 torr - 18.7 torr
Pressure of hydrogen gas = 739.3 torr
Therefore, the pressure of hydrogen gas is, 739.3 torr
