Step-By-Step Solution
Question 1
Balance: Fe2(SO4)3 + NH3 + H2O rightarrow Fe(OH)3 + (NH4)2SO4
Step 1
Write atoms and their counts for each compound:
- Fe2(SO4)3 has 2 Fe, 3 S, 12 O
- NH3 has 1 N, 3 H
- H2O has 2 H, 1 O
- Fe(OH)3 has 1 Fe, 3 O, 3 H
- (NH4)2SO4 has 2 N, 8 H, 1 S, 4 O
Step 2
Assign coefficients as variables:
- a Fe2(SO4)3
- b NH3
- c H2O
- d Fe(OH)3
- e (NH4)2SO4
Step 3
Set up element balance equations:
- Fe: 2a = d
- S: 3a = e
- N: b = 2e
- H: 3b + 2c = 3d + 8e
- O: 12a + c = 3d + 4e
Step 4
From Fe: d = 2a From S: e = 3a From N: b = 2e = 6a Substitute in H balance: 3b + 2c = 3d + 8e 3(6a) + 2c = 3(2a) + 8(3a) 18a + 2c = 6a + 24a 18a + 2c = 30a 2c = 12a c = 6a
Substitute in O balance: 12a + c = 3d + 4e 12a + 6a = 3(2a) + 4(3a) 18a = 6a + 12a 18a = 18a (True)
Step 5
Choose a lowest integer value for a, a = 1 Then:
- d = 2
- e = 3
- b = 6
- c = 6
Step 6
Write balanced equation: 1 Fe2(SO4)3 + 6 NH3 + 6 H2O rightarrow 2 Fe(OH)3 + 3 (NH4)2SO4
Question 2
Balance: NaOH + Cl2 rightarrow NaCl + NaClO3 + H2O
Step 1
Let coefficients be: a NaOH + b Cl2 rightarrow c NaCl + d NaClO3 + e H2O
Step 2
Balance Na: Na from left = a Na on right = c + d So, a = c + d
Balance Cl: From left: 2b From right: c + 3d So, 2b = c + 3d
Balance H: From left: a (from NaOH has one H) From right: 2e (in H2O) So, a = 2e
Balance O: From left: a (NaOH has one O) From right: 3d + e So, a = 3d + e
Step 3
From H and O equations: a = 2e (H) a = 3d + e (O) Set equal: 2e = 3d + e => e = 3d
From Na: a = c + d From Cl: 2b = c + 3d
Use e = 3d and a = 2e = 2(3d) = 6d Therefore a = 6d
Since a = c + d, 6d = c + d => c = 5d Also, 2b = c + 3d = 5d + 3d = 8d => b = 4d
Step 4
Choose d=1 (lowest integer) Then: a = 6 b = 4 c = 5 d = 1 e = 3
Step 5
Balanced equation: 6 NaOH + 4 Cl2 rightarrow 5 NaCl + 1 NaClO3 + 3 H2O
Question 3
Balance: KMnO4 + HCl rightarrow KCl + MnCl2 + H2O + Cl2
Step 1
Assign coefficients: a KMnO4 + b HCl rightarrow c KCl + d MnCl2 + e H2O + f Cl2
Step 2
Balance K: a = c
Balance Mn: a = d
Balance O: Left: 4a Right: e (water) So, 4a = e
Balance H: Left: b Right: 2e So, b = 2e = 2 (4a) = 8a
Balance Cl: Left: b = 8a Right: c + 2d + 2f = a + 2a + 2f = 3a + 2f So, 8a = 3a + 2f => 5a = 2f => f = (5/2)a
Step 3
Choose a=2 to get integer f: f = 5
Now:
- a=2
- c=2
- d=2
- e=4a=8
- b=8a=16
- f=5
Step 4
Write balanced equation: 2 KMnO4 + 16 HCl rightarrow 2 KCl + 2 MnCl2 + 8 H2O + 5 Cl2
Final Answer
-
Fe2(SO4)3 + 6 NH3 + 6 H2O rightarrow 2 Fe(OH)3 + 3 (NH4)2SO4
-
6 NaOH + 4 Cl2 rightarrow 5 NaCl + NaClO3 + 3 H2O
-
2 KMnO4 + 16 HCl rightarrow 2 KCl + 2 MnCl2 + 8 H2O + 5 Cl2
