BITSAT Chemistry Test Free Online Test 2026

The human body requires 9 essential amino acids that cannot be synthesized by the body and must be obtained through diet. These essential amino acids include histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

Option D is correct.

For a first-order reaction, k = (1/t) ln([A]0/[A]t).

Using ln x = 2.303 log x, we get k = (2.303/t) log([A]0/[A]t).

Here [A]t = [A]0/8 so [A]0/[A]t = 8. Therefore k = (2.303/24) log 8 min^-1, which is the expression given in option D.

Evaluating numerically: log 8 = 0.90309, so k = (2.303/24) × 0.90309 ≈ 0.08666 min^-1.

Li⁺ has highest ionization potential among the given species. The reason for this is after losing one electron, the Li⁺ ion has more stable inert gas configuration, i.e. 1s² . Secondly, it has smallest size among all the species due to less number of electrons and high effective nuclear charge.

The third transition series or 5d series corresponding to the filling of 5d sublevel consists of the following 10 elements of the 6thperiod: La (Atomic No.=57); Hf (Atomic No.= 72), Ta, W, Re, Os, Ir, Pt, Au and Hg (Atomic No.=80). Hence Re belongs to third transition series.

The standard emf of the cell Zn / Cu²⁺ is 1.10 V at 25^°C. When using solutions of 0.1 M Cu²⁺ and 0.1 M Zn²⁺, the emf can change due to concentration effects.

To calculate the emf under these conditions, we can apply the Nernst equation:

• The standard emf is 1.10 V.
• Both ions are at the same concentration, which will affect the overall emf.
• The actual emf will be lower than the standard emf due to concentration.

Therefore, the emf of the cell with 0.1 M solutions will be:

• 1.10 V

(c) Ethyl benzoate  The −Cl of chlorobenzene is weakly deactivating but has ortho-para directing influence. The −OH group of phenol is strongly activating the −OC2​H5​ group of ethoxybenzene is moderately activating but the −COOC2​H5​ group of ethylbenzoate is moderately deactivating and exerts meta directing influence on account of −I effect and −R effect.Read more on Sarthaks.com - https://www.sarthaks.com/3552109/which-one-of-the-following-will-undergo-meta-substitution-on-monochlorination