Answer
MnO₄ + 2H⁺ +3NO₂⁻ →3NO₃⁻ + Mn²⁺ +H₂O
Explanation
This is a redox reaction (oxidation-reduction reaction) which involves the transfer of electrons between two species. i.e
Mn + 6e⁻→Mn²⁺ (reduction)
3N³⁺- 6e⁻→3Mn⁵⁺(oxidation)
Mass = 5 g
volume = 20 cm³
density = mass / volume
therefore:
D = m / V
D = 5 / 20
D = 0.25 g/cm³
Answer : The
for this reaction is, -88780 J/mole.
Solution :
The balanced cell reaction will be,

Here, magnesium (Cu) undergoes oxidation by loss of electrons, thus act as anode. silver (Ag) undergoes reduction by gain of electrons and thus act as cathode.
The half oxidation-reduction reaction will be :
Oxidation : 
Reduction : 
Now we have to calculate the Gibbs free energy.
Formula used :

where,
= Gibbs free energy = ?
n = number of electrons to balance the reaction = 2
F = Faraday constant = 96500 C/mole
= standard e.m.f of cell = 0.46 V
Now put all the given values in this formula, we get the Gibbs free energy.

Therefore, the
for this reaction is, -88780 J/mole.
Answer:
1.
Explanation:
Hello,
In this case, for the given reaction we first assign the oxidation state for each species:

Whereas the half reactions are:

Next, we exchange the transferred electrons:

Afterwards, we add them to obtain:

By adding and subtracting common terms we obtain:

Finally, by removing the oxidation states we have:

Therefore, the smallest whole-number coefficient for Sn is 1.
Regards.