Which of the following compounds has both ionic and covalent bonds? MCQ with Answer and Explanation

Explanation:
Turmeric contains curcumin, a natural indicator that is yellow in acidic/neutral and turns reddish-brown in basic medium. Soap solution is basic (pH ~9-10), thus the stain changes color. This is used as a test for basicity. Vinegar or lemon juice (acid) can reverse the color. Soap is alkaline due to hydrolysis.

Explanation:
Brass: Cu + Zn. Bronze: Cu + Sn. Stainless steel: Fe + Cr + Ni. Duralumin: Al + Cu + Mg. Brass is used for musical instruments and utensils.

Explanation:
Nylon-6,6 is a condensation polymer formed by reaction between hexamethylenediamine and adipic acid, with elimination of water molecules. Polythene, Teflon, and PVC are addition polymers where monomers add without loss of small molecules. Condensation polymers often have amide or ester linkages. Another example is polyester (terylene). Nylon is a polyamide, known for strength and elasticity.