Name: Understanding Redox Titrations
Uploaded: 2019-07-19
Duration: 11 min 41 s
Description: Redox titration is a great way to identify whether a reaction is completed or not, where we know that reaction is complete, and it helps us find the strength...

Question

Write balanced net ionic equations for the following reactions in basic solution :

(a) ${Tl}_{2} O_{3} (s) + {NH}_{2} OH (aq) ⟶ TlOH (s) + N_{2} (g)$

(b) $Cu {({NH}_{3})}_{4}^{2 +} (aq) + S_{2} O_{4}^{2 -} (aq) ⟶ {SO}_{3}^{2 -} (aq) + Cu (s) + {NH}_{3} (aq)$

(c) $Mn (OH)_{2} (s) + {MnO}_{4}^{-} (aq) ⟶ {MnO}_{2} (s)$

Accepted Answer

If it says basic solution, you need to account for the fact that there will be no $H^{+}$ in the solution, it will be attracted to the ${OH}^{-}$ , and it will form water as a result. In this case, you need to add however many ${OH}^{-}$ to each side of the overall reaction for the $H^{+}$ that you have. This is basically an extension of the acidic solution, with one extra step.

(a) ${Tl}_{2} O_{3} (s) + {NH}_{2} OH (aq) ⟶ TlOH (s) + N_{2} (g)$ :-

For this we balance the atoms only because there is no spectator ions. But the aqueous ions present in the ionic form. So, we multiply the ammonium hydroxide by two to balance the nitrogen atom and $TlOH$ also by two.

$2 {Tl}_{2} O_{3} (s) + {NH}_{2}^{+} (aq) + {OH}^{-} (aq) ⟶ 2 TlOH (s) + 3 N_{2} (g)$

Now, balance the oxygen and hydrogen atoms by adding the water molecule,

$2 {Tl}_{2} O_{3} (s) + 6 {NH}_{2}^{+} (aq) + 6 {OH}^{-} (aq) ⟶ 2 TlOH (s) + 3 N_{2} (g) + 4 H_{2} O (l)$ .

(b) $Cu {({NH}_{3})}_{4}^{2 +} (aq) + S_{2} O_{4}^{2 -} (aq) ⟶ {SO}_{3}^{2 -} (aq) + Cu (s) + {NH}_{3} (aq)$

First balance the sulphur atoms,

$Cu {({NH}_{3})}_{4}^{2 +} (aq) + S_{2} O_{4}^{2 -} (aq) ⟶ 2 {SO}_{3}^{2 -} (aq) + Cu (s) + {NH}_{3} (aq)$

Now, balance the nitrogen atoms by multiplying the ammonia by four.

$Cu {({NH}_{3})}_{4}^{2 +} (aq) + S_{2} O_{4}^{2 -} (aq) ⟶ 2 {SO}_{3}^{2 -} (aq) + Cu (s) + 4 {NH}_{3} (aq)$

Now, balance the oxygen and hydrogen by adding the water molecule and hydroxide ion,

$Cu {({NH}_{3})}_{4}^{2 +} (aq) + S_{2} O_{4}^{2 -} (aq) + 4 {OH}^{-} ⟶ 2 {SO}_{3}^{2 -} (aq) + Cu (s) + 4 {NH}_{3} (aq) + 2 H_{2} O$

(c) $Mn (OH)_{2} (s) + {MnO}_{4}^{-} (aq) ⟶ {MnO}_{2} (s)$

First balance the $Mn$ atom,

$Mn {(OH)}_{2} (s) + {MnO}_{4}^{-} (aq) ⟶ 2 {MnO}_{2} (s)$

Now, balance the oxygen and hydrogen by adding the water molecule and hydroxide ion,

$Mn {(OH)}_{2} (s) + {MnO}_{4}^{-} (aq) ⟶ 2 {MnO}_{2} (s) + 2 {OH}^{-}$

Important Questions on Redox Reactions

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Write balanced net ionic equations for the following reactions in basic solution : (a) Tl2O3(s)+NH2OH(aq)⟶TlOH(s)+N2(g) (b) CuNH342+aq+S2O42-aq⟶SO32-aq+Cus+NH3aq (c) MnOH2s+MnO4-aq⟶MnO2s

Important Questions on Redox Reactions

Learn and Prepare for any exam you want !