Plus 2 Lecturer Mixed Practice Test #456

Question 1

A laboratory technician is performing a preliminary test for the presence of alkaloids in a plant extract. Which of the following reagents, commonly known as Mayer's reagent, would be used to detect alkaloids by forming a cream-colored precipitate?

Accepted Answer

C. Potassium Mercuric Iodide — Mayer's reagent is chemically known as potassium mercuric iodide and is widely used to precipitate alkaloids as cream-colored complexes. Wagner's reagent (iodine in potassium iodide) produces a reddish-brown precipitate, while Hager's and Scheibler's reagents also precipitate alkaloids but are distinct from Mayer's reagent.

Answer

A. Iodine in Potassium Iodide (Wagner's reagent)

Answer

B. Picric acid (Hager's reagent)

Answer

D. Phosphotungstic acid (Scheibler's reagent)

Question 2

Rani Lakshmibai of Jhansi died fighting the British at:‌​‍

Accepted Answer

Gwalior (17 June 1858) — After loss of Jhansi, fought alongside Tatya Tope. ‌​‍Killed in battle near Kotah-ki-Serai, Gwalior. Hugh Rose called her 'the best and bravest of the rebel leaders.'

Answer

Jhansi

Answer

Kalpi

Answer

Kanpur

Question 3

Which enzyme, primarily secreted in the stomach, is responsible for initiating the digestion of proteins?

Accepted Answer

C. Pepsin — Pepsin is a powerful proteolytic enzyme secreted by the chief cells of the stomach in its inactive form, pepsinogen, and activated by hydrochloric acid. It is responsible for beginning the breakdown of proteins into smaller polypeptides. Amylase digests carbohydrates, lipase digests fats, and trypsin is a pancreatic enzyme that continues protein digestion in the small intestine.

Answer

A. Amylase

Answer

B. Lipase

Answer

D. Trypsin

Question 4

Iguazu Falls between:‌​‍

Accepted Answer

Argentina-Brazil — Argentina-Brazil border.‌​‍

Answer

Brazil-Paraguay

Answer

Peru-Chile

Answer

Colombia-Venezuela

Question 5

RCEP (Regional Comprehensive Economic Partnership) — India:‌​‍

Accepted Answer

Withdrew from RCEP negotiations in 2019 — India withdrew in Nov 2019 citing concerns about Chinese imports. ‌​‍RCEP (15 nations, world's largest trade bloc) signed Nov 2020 without India.

Answer

Joined

Answer

Founded it

Answer

Never negotiated

Question 6

How many hours is Indian Standard Time (IST) ahead of GMT?‌​‍

Accepted Answer

5.5 hrs — IST = GMT+5:30.

Answer

4 hrs

Answer

6 hrs

Answer

3 hrs

Question 7

Dark spot at centre of Newton's rings (reflected light) is due to:‌​‍

Accepted Answer

Destructive interference (π phase on denser medium reflection) — Not in XI SCERT. ‌​‍At point of contact, path difference ≈ 0 but π phase change on glass reflection causes destructive interference.

Answer

Constructive

Answer

Dispersion

Answer

Diffraction

Question 8

Nixon-Mao meeting (1972) marked:‌​‍

Accepted Answer

US-China diplomatic opening — President Nixon visited China Feb 1972 — historic opening. ‌​‍Shanghai Communiqué. US recognised PRC officially 1979 (Carter).

Answer

USSR-China alliance

Answer

Vietnam peace

Answer

Cuban crisis

Question 9

The sex of a human child is determined by:‌​‍

Accepted Answer

Father's sperm (X or Y chromosome) — Mother always gives X; father gives X (daughter) or Y (son).‌​‍

Answer

Mother's chromosome

Answer

Environment

Answer

Blood type

Question 10

The law of heredity was given by:‌​‍

Accepted Answer

Gregor Mendel — Gregor Mendel (Father of Genetics) established the laws of heredity through pea plant experiments.‌​‍

Answer

Darwin

Answer

Lamarck

Answer

Watson

Plus 2 Lecturer Mixed Practice Test #456