Multiple Choice Questions

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Borax bead test of Cr (chromium) is :

  • green

  • blue

  • violet

  • brown


A.

green

In borax bead test

Cu2+ gives bluish green bead.

Cr3+ gives dark green bead.

Ni2+ gives brown bead.

Mn2+ gives pink-bead.


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Graphite is a soft solid lubricant extremely difficult to melt. The reason for this anomalous behaviour is that, graphite

  • is a non-crystalline substance

  • is an allotropic form of diamond

  • has molecules of variable molecular masses like polymers

  • has carbon atoms arranged in large plates of rings of strongly bound carbon atoms with weak interplate bonds


White lead is

  • PbCO3PbO

  • PbCO3

  • Pb(OH)2.2PbCO3

  • PbSO4.PbO


Buckminster fullerene is :

  • pure graphite

  • C-60

  • diamond

  • C-90


In silica (SiO2), each silicon atom is bonded to

  • two oxygen atoms

  • four oxygen atoms

  • one silicon and two oxygen atoms

  • one silicon and four oxygen atoms


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Dry ice is:

  • solid SO2

  • Solid NH3

  • Solid O2

  • Solid CO2


The structure of diborane (B2H6) contains

  • four 2C-2e- bonds and four 3C-2e- bonds

  • two 2C-2e- bonds and two 3C-3e- bonds

  • two 2C-2e- bonds and four 3C-2e- bonds

  • four 2C-2e- bonds and two 3C-2e- bonds


Which of the following metallic oxide exhibit amphoteric nature?

  • CaO

  • Al2O3

  • Na2O

  • BaO


The elements commonly used for making transistors are :

  • C and Si

  • Ga and In

  • P and As

  • Si and Ge


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Crystalline form of silica is called :

  • crystalline silicon

  • quartz

  • rock

  • talc


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