Question

According to preferential discharge theory, out of the number of ions the one which requires ___________ energy will be liberated ________ at a given electrode. Six carbon atoms linked in a straight chain.
a. Least, first
b. Least, last
c. Higher, first
d. Highest, last

Answer 1

Hint: To answer this question, we should first know about preferential discharge theory. This theory tells us about discharging of electrons from a particular electrode.

Complete step by step solution:
We should know about preferential discharge theory. This theory states that, if we find more than one type of the ions that are attracted towards a particular electrode. Then we should know that the ion that should first get discharged is one which needs least energy or ions that have the lower discharge potential or which occur low in electrochemical series.
The factors that affect the preferential discharge theory are:
The position of ion in electrochemical series
The concentration of ions also affects the preferential discharge of ions in the electrochemical series.
And we should note that, nature of electrodes also affects the preferential discharge of ions.
Now, from the above theory we will try to complete the paragraph that is given in the question. So, we know that the ions which required the least energy will be liberated first at a given electrode. And we know that, cation that has a cover position in the electrochemical series is preferentially discharged whereas, an anion that has higher position in electrochemical series is preferentially discharged.
So, from this the completed paragraph that was given in the question as follows:
According to preferential discharge theory, out of the number of ions the one which requires least energy will be liberated first at a given electrode. Six carbon atoms linked in a straight chain.

So, now we can say that option A is correct.

Note: We should know that the potential at which the ion is discharged or deposited on the appropriate electrode is termed the discharge or deposition potential, (DP). The values of the discharge potential are different for different ions. We should now know about the decreasing order of discharge potential or increasing order of the deposition of some of the ions. It can be given as follows:
For cations it as follows: \[L{{i}^{+}},N{{a}^{+}},C{{a}^{+}},M{{g}^{2+}},A{{l}^{3+}},Z{{n}^{2+}},F{{e}^{2+}},N{{i}^{2+}},{{H}^{+}},C{{u}^{2+}},H{{g}^{2+}},A{{g}^{+}},A{{u}^{+}}\]
For anions: \[SO_{4}^{2-},NO_{3}^{-},O{{H}^{-,}}C{{l}^{-}},B{{r}^{-,}}{{I}^{-}}\]