Class 12th

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:

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:

Match List-I with List-II

Choose the correct answer from the options given below :

For a first order reaction A → Products, initial concentration of A is 0.1M, which becomes 0.001 after 5 minutes. Rate constant for the reaction min^-1 is: