Class 12th

The order of energy absorbed which is responsible for the color of complexes.
(A) [Ni(H₂O)₂(en)₂]²⁺
(B) [Ni(H₂O)₄(en)]²⁺
(C) [Ni(en)₃]²⁺

A nucleus of mass number 189 splits into two nuclei having mass number 125 and 64 . The ratio of radius of two daughter nuclei respectively is :

Copper crystallises in fee unit cell with cell edge length of 3.608 × 10^-8 cm. The density of copper is 8.92 g cm^-3. Calculate the atomic mass of copper.

In the neutral or faintly alkaline medium, KMnO₄ oxidises iodide into iodate. The change in oxidation state of manganese in this reaction is from:

The electron concentration in an n-type semiconductor is the same as hole concentration in a p-type semiconductor. An external field (electric) is applied across each of them. Compare the currents in them.

Find the emf of the cell in which the following reaction takes place at 298 K
Ni(s) + 2Ag⁺(0.001M) → Ni²⁺(0.001M) + 2Ag(s)
(Given that E°cell = 1.05 V, 2.303RT/F = 0.059 at 298 K)

Given below are two statements:

Statement I: In Lucas test, primary, secondary and tertiary alcohols are distinguished on the basis of their respectively with conc. HCl + ZnCl₂, known as Lucas Reagent.
Statement II: Primary alcohols are most reactive and immediately produce turbidity at room temperature on reaction with Lucas Reagent

In the light of the above statements, choose the most appropriate answer from the options given below:

A lens of large focal length and large aperture is best suited as an objective of an astronomical telescope since:

Match List -I with List -II

List -I (Ores)
(a) Haematite
(b) Magnetite
(c) Calamine
(d) Kaolinite

List-II (Composition)
(i) Fe₃O₄
(ii) ZnCO₃
(iii) Fe₂O₃
(iv) [Al₂(OH)₄Si₂O₅]

Choose the correct answer from the options given below:

The product formed from the following reaction sequence is: