The balanced equation for the above reaction is
2Al + 6H₂O ---> 2Al(OH)₃ + 3H₂
stoichiometry of Al to H₂ is 2:3
number of Al moles reacted - 78.33 g / 27 g/mol = 2.901 mol
according to molar ratio
2 mol of Al forms - 3 mol of H₂
therefore 2.901 mol of Al - forms 3/2 x 2.901 = 4.352 mol
molar volume states that 1 mol of any gas occupies a volume of 22.4 L at STP
if 1 mol occupies 22.4 L
then 4.352 mol occupies - 22.4 L/mol x 4.352 mol = 97.48 L
volume occupied by H₂ is 97.48 L
B. Intake valve is the correct answer
The Lewis structure of PF3 shows that the central phosphorus atom has one non bonding and three bonding electron pairs. In this compound each Phosphorus atom contributes 5 valence electrons while each fluoride contributes 7 valence electrons making a total of 26 valence electrons. The central Phosphorus atom forms single bonds with each of the fluoride atoms. Phosphorus, therefore ends up with a non-bonding pair since the fluoride atoms already have 8 electrons around them. <span />
<span>F can only have oxidation number of -1
The overall compound has an oxidation number of -1
You have 6 Fs, so 6(-1) = -6
charge from F
X = oxidation number of P
x + (-6) = -1
solve for
x = +5</span>
