Answer:
8M IM NOT SURE SO. IF YOU CAN GET A CLEARED PICTURE OF IT WOULD REALLY HELP
Answer : The balanced molecular equation will be:

Explanation :
Molecular equation : It is a balanced chemical reaction in which the ionic compounds are expressed as the molecules instead of component ions.
According to the question, when iron react with copper (II) sulfate then it react to give iron (II) sulfate and copper as a product. In this reaction, iron is more reactive metal than the copper metal. So, it can easily displace copper metal form the solution.
The balanced molecular equation will be:

The third one is correct, not sure abt another one
Answer:
(a) adding 0.050 mol of HCl
Explanation:
A buffer is defined as the mixture of a weak acid and its conjugate base -or vice versa-.
In the buffer:
1.0L × (0.10 mol / L) = 0.10 moles of HF -<em>Weak acid-</em>
1.0L × (0.050 mol / L) = 0.050 moles of NaF -<em>Conjugate base-</em>
-The weak acid reacts with bases as NaOH and the conjugate base reacts with acids as HCl-
Thus:
<em>(a) adding 0.050 mol of HCl:</em> The addition of 0.050moles of HCl produce the reaction of 0.050 moles of NaF producing HF. That means after the reaction, all NaF is consumed and you will have in solution just the weak acid <em>destroying the buffer</em>.
(b) adding 0.050 mol of NaOH: The NaOH reacts with HF producing more NaF. Would be consumed just 0.050 moles of HF -remaining 0.050 moles of HF-. Thus, the buffer <em>wouldn't be destroyed</em>.
(c) adding 0.050 mol of NaF: The addition of conjugate base <em>doesn't destroy the buffer</em>