Answer:
C: The Fe is not balanced
Explanation:
The reaction expression is given as:
Fe₂O₃ + 3H₂ → Fe + 3H₂O
The problem here is to find the specie that is not balanced.
Number of moles
Specie Reactant Product
Fe 2 1
O 3 3
H 6 6
So, we see that Fe is not balanced.
Before addition of HCl,
conc. of CH3COOH = 0.450 M
conc. of CH3COONa = 0.550 M
After addition of 0.08 M HCl, following reaction occurs in system:
HCl + CH3COONa ↔ CH3COOH + NaCl
Thus, in reaction system conc. of CH3COOH will increase to 0.53 M (0.08M + 0.450M)
And, conc to CH3COONa will reduce to 0.47 M (0.550M - 0.08M)
Now, conc. of H+ ions = ka
![\frac{[acid]}{[conjugated base]}](https://tex.z-dn.net/?f=%20%5Cfrac%7B%5Bacid%5D%7D%7B%5Bconjugated%20base%5D%7D)
where ka = dissociation constant for acid = 10^-5 for Ch3COOH
∴ conc. of H+ ions =

= 1.1277 x 10^-5
Now, pH = -log [H+] = -log (1.1227 x 10^-5) = 4.94
178.87 grams of sulphur dioxide is formed according to the equation given.
Explanation:
The balanced chemical reaction for the process is:
4 FeS2 + 11 O2 ⇒ 2Fe2O3(-) + 8 SO2
the reaction involving FeS and oxygen having balanced chemical equation as:
moles of oxygen given as 3.84
so when 11 moles of O2 reacts to form 8 moles SO2
3.84 moles of oxygen reacts to form x moles of SO2
= 
x = 
2.792 moles of sulphur dioxide will be formed
The mass can be calculated as number of moles x molar mass of 1 mole of SO2
= 2.792 x 64.066
= 178.87 grams of sulphur dioxide is formed.