Class 12th

The topics focused on while preparing the Current Electricity NCERT solutions are:

• Ohm's law

• Drift velocity

• Resistivity vs temperature

• Combination of cells

• Kirchhoff's rules and 

• Wheatstone bridge

Tollen's reagent oxidises aldehydes into carboxylate ion whereas ketone is not oxidised by tollen's reagent.

Formation of Conjugated diene in option 3 make the given reactant most reactive towards dehydration in acidic conditions.

Reaction follows SN1 pathway involving Benzylic carbocation.

Ethylene diamine, en is bidentate, chelating ligand. Chelating ligands increase stability due to higher entropy factor.

The highest oxidation number corresponding to the group number in transition metal oxides is attained in Sc? O? to Mn? O? CrO is basic but Cr? O? is amphoteric.

Note: All the transition metals except scandium form MO oxides which are ionic (Only for 3d series, this statement is true)

Hence, (A), (C) and (D) are incorrect. But not given in the options.

H? S? O? , peroxodisulphuric acid (Two S-OH, Four S = O, One S – O – O – S )

H? SO? , sulphurous acid (Two S-OH, One S = O bond)

H? S? O? , pyrosulphuric acid (Two S-OH, Four S=O, One S-O-S bond)

H? SO? , sulphuric acid (Two S – OH, Two S = O )

Fe? O? + CO → 2FeO + CO?

The above reaction takes place at 500 – 800 K in blast furnace.

Pumice stone is an example of solid sol. In this type of colloid, the dispersion medium is solid and the dispersion phase is gas.

One edge of an cube is common to four unit cells. Hence One edge centre OV contribute 1/4 to one unit cell.