Which of the following indicators is synthetic? MCQ with Answer and Explanation

Explanation:
In an electrochemical cell, reduction (gain of electrons) always occurs at the cathode, regardless of whether the cell is electrolytic or galvanic. At the anode, oxidation (loss of electrons) occurs. Memory aid: 'RED CAT' (REDuction at CAThode), 'AN OX' (OXidation at ANode). In electrolysis, the cathode is connected to the negative terminal of the battery, attracting cations which get reduced.

Explanation:
Iodine-131 is a radioactive isotope used to treat thyroid disorders including goitre and cancer. Carbon-14 for dating, Cobalt-60 for cancer therapy, Uranium-235 as fuel in nuclear reactors. Non-radioactive isotopes are used as tracers. Goitre is often caused by iodine deficiency, but radioactive iodine can be used therapeutically.

Explanation:
PVC (polyvinyl chloride) is a polymer of vinyl chloride (CH₂=CHCl). It is used in pipes, electrical insulation, and flooring. It can be rigid (uPVC) or flexible with plasticizers. It is a thermoplastic. Chlorate/carbon/carbide are not correct expansions.