IUPAC name of Na₃[Co(NO₂)₆] is

• sodium hexanitrito cobaltate (II)

• sodium hexanitro cobaltate (III)

• sodium hexanitrito cobaltate (III)

• sodium cobaltnitrite

Acidified sodium fusion extract on addition of ferric chloride solution gives blood red colouration which confirms the presence of

• S and Cl

• N and S

• N

• S

During the extraction of gold the following reactions take place

Au + CN^- + H₂O $\stackrel{{\mathrm{O}}_2}{\to }$ [X]

             [X] + Zn → [Y] + Au

X and Y are respectively

• [Au(CN)₂]^- and [Zn(CN)₆]^4-

• [Au(CN)₄]^2- and [Zn(CN)₄]^2-

• [Au(CN)₄]^3- and [Zn(CN)₄]^2-

• [Au(CN)₂]^- and [Zn(CN₄)]^2-

The number of gram molecules of chlorine in 6.02 × 10²⁵ hydrogen chloride molecules is

• 10

• 100

• 50

• 5

Which of the following forms a colourless solution in aqueous medium?

• Cr³⁺

• C³⁺

• Sc³⁺

• Ti³⁺

When a sulphur sol is evaporated sulphur is obtained. On mixing with water sulphur sol is not formed. The sol is

• lyophilic

• reversible

• hydrophobic

• hydrophilic

When conc. H₂SO₄ is heated with P₂O₅, the acid is converted into

• sulphur trioxide

• sulphur dioxide

• sulphur

• a mixture of sulphur dioxie and sulphur trioxide

48.

When KBr is dissolved in water, K⁺ ions are

• hydrated

• hydrolysed

• reduced 

• oxidised

The noble gas mixture is cooled in a coconut bulb at 173 K. The gases that are not adsorbed are

• Ne and Xe

• He and Xe

• Ar and Kr

• He and Ne

Identify the ore not containing iron.

• limonite

• siderite

• carnallite

• chalcopyrites