(i) For weak electrolytes at infinite dilution, molar conductance can't be calculated experimentally because the graph of molar conductance versus concentration is not linear and does not extrapolate to a definite value. A gas electrode is an electrode that consists of a metal in contact with a gas, such as hydrogen, chlorine, or oxygen. An example of a gas electrode is the standard hydrogen electrode (SHE), which has the following half-reaction: $2H^+ (aq) + 2e^- \rightarrow H_2 (g)$ 

 (ii) The direction of micelle formation by sodium stearate in water is such that the hydrocarbon part (the long alkyl chain) is oriented towards the center of the sphere and the ionic part (the carboxylate group) is oriented towards the surface of the sphere. This is because the hydrocarbon part is hydrophobic (water-hating) and the ionic part is hydrophilic (water-loving). The micelle minimizes the contact of the hydrophobic part with water and maximizes the contact of the hydrophilic part with water.

 (iii) The fundamental difference in electronic configuration between lanthanoids and actinoids is that in lanthanoids, the electrons enter the 4f orbital, whereas in actinoids, the electrons enter the 5f orbital. The general electronic configuration of lanthanoids is $[Xe] 4f^{1-14} 5d^{0-1} 6s^2$ and the general electronic configuration of actinoids is $[Rn] 5f^{0-14} 6d^{0-2} 7s^2$ where [Xe] and [Rn] represent the electronic configurations of xenon and radon, respectively. $ Cu+$ salt is colorless but $Cu^{2+}$ salt is colored because $ Cu+$ has a completely filled 3d orbital $(3d^{10}) $ and $Cu^{2+ }$ has one electron less in the 3d orbital $(3d^9)$. When light falls on $Cu^{2+ }$ions, some of the electrons in the 3d orbital can be excited to higher energy levels, resulting in the absorption of some wavelengths of light and the reflection of others. This gives rise to the color of $Cu^{2+}$ salts. $Cu^+$ ions, on the other hand, cannot undergo such transitions because they have no vacant spaces in the 3d orbital. Therefore, they do not absorb any light and appear colorless. 

 (iv) Narcotic analgesics are applied when there is a need for relief of short-term, intense pain, such as after surgery or due to a medical condition⁶. Narcotic analgesics may also be used to relieve pain due to cancer, or for palliative or end-of-life care. Narcotic analgesics work by binding to opioid receptors in the brain and spinal cord, blocking the transmission of pain signals and producing a feeling of euphoria⁶. Narcotic analgesics can be taken orally or given intravenously 


(IV). However, they also carry serious risks, such as addiction, dependence, tolerance, overdose, and side effects. Therefore, they should be used with caution and under strict monitoring.