Answer the following: Complete and balance the following reactions: (a) ____ + ____ + ____ + ____…
Answer the following:
(i)[2.0]
Complete and balance the following reactions:
(a) $\text{K}_2\text{Cr}_2\text{O}_7 + \text{H}_2\text{SO}_4 + \text{KI} \longrightarrow$ ____ + ____ + ____ + ____
(b) $\text{KMnO}_4 + \text{H}_2\text{SO}_4 + \text{FeSO}_4 \longrightarrow$ ____ + ____ + ____ + ____
(ii)[1.0]
Which ion, $\text{Co}^{2+}$ or $\text{Zn}^{2+}$, is attracted to a magnetic field? Give reasons.
(Atomic Number of $\text{Co} = 27$ and $\text{Zn} = 30$)
Answer
Answer (i)
AIWritten by AI (gemini) - it can contain mistakes.
(a) $\text{K}_2\text{Cr}_2\text{O}_7 + 7\text{H}_2\text{SO}_4 + 6\text{KI} \longrightarrow \text{Cr}_2(\text{SO}_4)_3 + 4\text{K}_2\text{SO}_4 + 3\text{I}_2 + 7\text{H}_2\text{O}
(b) $2\text{KMnO}_4 + 8\text{H}_2\text{SO}_4 + 10\text{FeSO}_4 \longrightarrow \text{K}_2\text{SO}_4 + 2\text{MnSO}_4 + 5\text{Fe}_2(\text{SO}_4)_3 + 8\text{H}_2\text{O}
Answer (ii)
AIWritten by AI (gemini) - it can contain mistakes.
$\text{Co}^{2+}$ is attracted to a magnetic field.
Reason:
$\text{Co}^{2+}$ ($Z = 27$) has the electronic configuration $[\text{Ar}] 3d^7$. In the $3d$ subshell, there are 3 unpaired electrons ($n = 3$), making the ion paramagnetic, so it is attracted to a magnetic field.
In contrast, $\text{Zn}^{2+}$ ($Z = 30$) has the electronic configuration $[\text{Ar}] 3d^{10}$, in which all electrons are paired ($n = 0$), making it diamagnetic (repelled by a magnetic field).
From ISC 2026 Chemistry Paper 1, question 13.