Science (English Medium) इयत्ता १२ - CBSE Important Questions

Write the structure of the major product in each of the following reaction :

What is the significance of leaching in the extraction of aluminium?

In the following pair of halogen compounds, which compound undergoes a faster S_N1 reaction?

Arrange the compounds of the following set in order of reactivity towards S_N2 displacement:

2-Bromo-2-methylbutane, 1-Bromopentane, 2-Bromopentane

Out of PbS and PbCO₃ (ores of lead), which one is concentrated by froth floatation process preferably?

Given reasons: S_N1 reactions are accompanied by racemization in optically active alkyl halides.

Account for the following :

Iron on reaction with HCl forms FeCl₂ nd not FeCl₃.

What happens when Silver is leached with NaCN in the presence of air? 

Out of (CH₃)₃ C-Br and (CH₃)₃ C-I, which one is more reactive towards S_N1 and why? 

ICl is more reactive than I₂.

Write the IUPAC name of the given compound:

Write the structures of the following molecule: 

H₂SO₃

Give reasons for the following : H₂Te is the strongest reducing agent amongst all the hydrides of Group 16 elements.

Give reasons for the following : Phenol is more acidic than ethanol.

Give reasons for the following : Boiling point of ethanol is higher in comparison to methoxymethane.

Write the structures of the main products when acetone (CH₃ − CO − CH₃) reacts with the following reagents :

CH₃MgBr and then H₃O⁺

Draw the structures of the following:
(1) HClO₄
(2) H₃PO₃

Complete the following equation: 

\[\ce{XeF2 + H2O ->}\]

Give reasons Fluoride ion has higher hydration enthalpy than chloride ion.

Give reason for the following:

Red phosphorus is less reactive than white phosphorus.