Question:medium

An element of p-block forms a species of type EH$_4^{+}$, which when passed through a basic solution of K$_2$[HgI$_4$], forms a brown ppt. Select the correct option:

Show Hint

In p-block elements, the formation of brown precipitates with mercury salts is a characteristic reaction of ammonia (NH$_3$).
Updated On: Feb 4, 2026
  • Element E has maximum covalency equal to 5.
  • Brown ppt. formed is HgO. Hg(NH$_3$)I.
  • Element E has maximum electron affinity in its group.
  • EH$_3$ is phosphine.
Show Solution

The Correct Option is B

Solution and Explanation

Concept: The total moment of inertia is the sum of the moments of inertia of the individual spheres. Since the axis does not pass through the centers (it is tangential), we use the Parallel Axis Theorem: \(I = I_{cm} + md^2\), where \(I_{cm} = \frac{2}{5}mR^2\) for a solid sphere and \(d=R\).
Step 1: Calculate \(I_1\). \(m_1 = 10\), \(R_1 = 0.2\) m. \[ I_1 = \frac{2}{5}m_1 R_1^2 + m_1 R_1^2 = \frac{7}{5}m_1 R_1^2 \] \[ I_1 = 1.4 \times 10 \times (0.2)^2 = 14 \times 0.04 = 0.56\,\text{kg m}^2 \]
Step 2: Calculate \(I_2\). \(m_2 = 5\), \(R_2 = 0.1\) m. \[ I_2 = \frac{7}{5}m_2 R_2^2 \] \[ I_2 = 1.4 \times 5 \times (0.1)^2 = 7 \times 0.01 = 0.07\,\text{kg m}^2 \]
Step 3: Total Moment of Inertia. \[ I_{total} = I_1 + I_2 = 0.56 + 0.07 = 0.63\,\text{kg m}^2 \] \[ \boxed{I = 0.63\,\text{kg m}^2} \]
Was this answer helpful?
0