First find the oxidation states of the various atoms:
<span>in Cr2O2 2- Cr @ +1; In NH3 N @ +3; in CrO3 Cr @ +3, N2 N @ 0 </span>
<span>Note that N gained electrons, ie, was reduced; Cr was oxidized </span>
<span>Now there is a problem, because B has NH4+ which the problem did not, and is not balanced, showing e- in/out </span>
<span>B.NH4+ → N2 </span>
<span>Which of the following is an oxidation half-reaction? </span>
<span>A.Sn 2+ →Sn 4+ + 2e- </span>
<span>Sn lost electrons so it got oxidized</span>
I think that it is qualitative data
Answer:
Standard free-energy change at 
is 
Explanation:
Oxidation: 
Reduction: 
--------------------------------------------------------------------------------------
Overall: 
Standard cell potential, 
So, 
We know, standard free energy change at (
): 
where, n is number of electron exchanged during cell reaction, 1F equal to 96500 C/mol
Here n = 2
So, 
The answer is D. Most common semiconducting materials are crystalline solids. A<span>morphous and liquid semiconductors are also known to be.</span>
