State the meaning of the term electrochemical series - AQA - A-Level Chemistry - Question 8 - 2021 - Paper 1
Question 8
State the meaning of the term electrochemical series.
The electrochemical series is a list of electrode potentials arranged in numerical order. It indicates the lik... show full transcript
Worked Solution & Example Answer:State the meaning of the term electrochemical series - AQA - A-Level Chemistry - Question 8 - 2021 - Paper 1
Step 1
State two conditions needed for the following half-cell to have E°' = 0.00 V
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The concentration of the reactants and products must be 1 M.
The temperature must be maintained at 25°C.
Step 2
Identify the weakest reducing agent in Table 8.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The weakest reducing agent in Table 8 is [Co(H2O)6]3+.
Step 3
Use half-equations from Table 8 to deduce an equation for the reduction of VO2+ to form VO2+ in aqueous solution by iron.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The reduction equation can be expressed as:
3extVO2++2extFe→3extVO2++2extFe3+
Step 4
Use data from Table 8 to explain why [Co(H2O)6]3+(aq) will undergo a redox reaction with [Fe(H2O)6]2+(aq)
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The electrochemical potentials indicated in Table 8 show that [Co(H2O)6]3+ has a higher potential than [Fe(H2O)6]2+. Therefore, it can oxidize [Fe(H2O)6]2+ to [Fe(H2O)6]3+.
Suggest why the two cobalt(III) complex ions in Table 8 have different electrode potentials.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The different ligand environments around the cobalt(III) ions affect their stability and reactivity. Ligands with different coordinating abilities or electron-donating properties can alter the electrode potential of the cobalt ions.
