Who proposed the 'plum pudding' model of the atom? MCQ with Answer and Explanation

Explanation:
Hydrochloric acid (HCl) is commonly used for pickling (cleaning) steel to remove rust and scale (iron oxides) before further processing like galvanizing or plating. Reaction: Fe₂O₃ + 6HCl → 2FeCl₃ + 3H₂O. Sulfuric acid is also used. Nitric acid is an oxidizer and would passivate some metals. Acetic acid is too weak.

Explanation:
A separating funnel allows immiscible liquids to form layers; the denser liquid is drained from the bottom. Fractionating column is for miscible liquids with close boiling points, condenser for distillation, centrifuge for separating fine solids or liquids of different densities by spinning.

Explanation:
In electrolysis, the external power source forces non-spontaneous reactions. Electrons are drawn away from the anode, making it positive. Thus anode is connected to the positive terminal. In a galvanic (voltaic) cell, anode is negative. Remember: electrolytic cell – anode positive; oxidation still occurs at anode. Electroplating uses this setup: object to be plated is cathode, source metal is anode.