The amorphous form of silica is:

• Tridymite

• Quartz

• Kieselguhr

• Cristobalite

The correct statements among I to III regarding group 13 element oxides are,

(I) Boron trioxide is acidic.

(II) Oxides of aluminium and gallium are amphoteric.

(III) Oxides of indium and thallium are basic.

• (I) and (II) only

• (I), (II) and (III)

• (I) and (III) only

• (II) and (III) only

13.

The layer of atmosphere between 10 km to 50 km above the sea level is called as :

• Thermosphere

• Troposhere

• Mesosphere

• Stratosphere

Assertion: For the extraction of iron, haematite ore is used.

Reason: Haematite is a carbonate ore of iron.

• Both the assertion and reason are correct and the reason is the correct explanation for the assertion.

• Only the assertion is correct.

• Both the assertion and reason are correct, but the reason is not the correct explanation for the assertion

• Only the reason is correct

A solution of Ni(NO₃)₂ is electrolysed between platinum electrodes using 0.1 Faraday electricity. How many mole of Ni will be deposited at the cathode?

• 0.10

• 0.15

• 0.20

• 0.05

The structures of beryllium chloride in the solid state and vapour phase, respectively, are :

• Chain and chain

• Chain and Dimeric

• Dimeric and dimeric

• Dimeric and chain

10 mL of 1 mM surfactant solution forms a monolayer covering 0.24 cm² on a polar substrate. If the polar head is approximated as a cube, what is its edge length?

• 2.0 pm

• 0.1 nm

• 2.0 nm

• 1.0 pm

The one that is not a carbonate ore is:

• Calamine

• Siderite

• Malachite

• Bauxite

The maximum number of possible oxidation states of actinoides are shown by-

• Neptunium (Np) and plutonium (Pu)

• Nobelium (No) and lawrencium (Lr)

• Berkelium (Bk) and californium (Cf)

• Actinium (Ac) and throrium (Th)

Molal depression constant for a solvent is 4.0 K kg mol^-1. The depression in the freezing point of the solvent for 0.03 mol kg^-1 solution of K₂SO₄ is : (Assume complete dissociation of the electrolyte)

• 0.24 K

• 0.12 K

• 0.18 K

• 0.36 K