Science (English Medium) Class 12 - CBSE Question Bank Solutions

What is the role of depressants in the froth floatation process?

Complete the following equations:

`2MnO_4^(-)+16H^++5S^(2-)rarr`

How will you convert: Phenol to 2, 4, 6 − trinitrophenol?

Write the fomulae of the following compounds :

Tetraaquodichlorochromium (III) chloride

Write the fomulae of the following compounds

Potassium tetracyanoaurate (III) ion

Write the product when D-glucose reacts with conc. HNO₃.

Arrange the following in the increasing order of their pK_b values:

C₆H₅NH₂, C₂H₅NH₂, C₆H₅NHCH₃

Name the reagents used in the following reactions:

Complete the following equation :

Write the structures of A, B and C in the following reactions :

A first order reaction takes 10 minutes for 25% decomposition. Calculate t_1/2 for the reaction.

(Given : log 2 = 0.3010, log 3 = 0.4771, log 4 = 0.6021)

Show that the time required for 99% completion is double of the time required for the completion of 90% reaction.

Which of the following isomers is more volatile:

o-nitrophenol or p-nitrophenol?

Complete the following chemical equations :

Cu + H₂SO₄(conc.) →

In reference to Freundlich adsorption isotherm, write the expression for adsorption of gases on solids in the form of an equation.

Glucose on reaction with HI gives n-hexane. What does it suggest about the structure of glucose?

Give the structures of A, B and C in the following reactions :

Calculate emf of the following cell at 298 K:

\[\ce{Mg_{(s)} | Mg^{2+} (0.1 M) || Cu^{2+} (0.01) | Cu_{(s)}}\]

[Given \[\ce{E^{\circ}_{cell}}\] = +2.71 V, 1 F = 96500 C mol^–1]

Name a member of the lanthanoid series that is well-known to exhibit +2 oxidation state.

Give the structures of A, B and C in the following reactions :