41.

Cooking is fast in a pressure cooker, because

• food particles are effectively smashed

• water boils at higher temperature inside the pressure cooker

• food is cooked at constant volume

• loss of heat due to radiation is minimum

The ore that is concentrated by froth floatation process is

• zincite

• cinnabar

• bauxite

• malachite

Rate of physical adsorption increases with

• decrease in surface area

• decrease in temperature

• decrease in pressure

• increase in temperature

The temperature of the slag zone in the metallurgy of iron using blast furnace is

• 1200 - 1500°C

• 1500 - 1600 °C

• 400 - 700°C

• 800 - 1000°C

The function of Fe(OH)₃ in the contact process is

• to remove arsenic impurity

• to detect colloidal impurity

• to remove mositure

• to remove dust particle

In which of the following, NH₃ is not used?

• Tolles's reagent

• Nessler's reagent

• Group reagent for the analysis of IV group basic radicals

• Group reagent for the analysis of III group basic radicals

Argon is used

• in filling airships

• to obtain low temperature

• in high temperature welding

• in radiotherapy for treatment of cancer

The incorrect statement in respect of chromyl chloride test is

• formation of red vapours

• formation of lead chromate

• formation of chromyl chloride

• liberation of chlorine

The IUPAC name of [Co(NH₃)₅ONO]²⁺ ion is

• penta ammine nitrito cobalt (IV) ion

• penta ammine nitrito cobalt (III) ion

• penta ammine nitro cobalt (III) ion

• penta ammine nitro cobalt (IV) ion

In electrophilic aromatic substitution reaction, the nitro group is meta directing because it

• decreases electron density at ortho and para positions

• decreases electron density at meta position

• increases electron density at meta position

• increases electron density at ortho and para positions