An element 'X' has electronic configuration 2,8,7. It belongs to: MCQ with Answer and Explanation

Explanation:
Pepsin is a protease secreted in the stomach; it hydrolyzes proteins into peptides. Ptyalin (salivary amylase) digests starch; amylase also breaks starch; lipase digests fats.

Explanation:
Cement undergoes hydration reactions: water reacts with cement compounds (C₃S, C₂S, C₃A) to form complex hydrated silicates and aluminates (e.g., C-S-H gel) along with Ca(OH)₂. This process causes setting and hardening, forming a rigid, rock-like mass. It is exothermic. Gypsum controls initial setting. Proper curing is necessary for strength development.

Explanation:
Neutralization is the reaction of an acid and a base to form salt and water. HCl (acid) + NaOH (base) → NaCl (salt) + H₂O. Option A is combination; C is decomposition; D is displacement.