An example of a double salt is
Potash Alum, K2SO4. Al2(SO4). 24H2O is a double salt.
The substance used as a smoke screen in warfare is
SiCl4 gets hydrolysed in moist air and gives white fumes which are used as a smoke screen in warfare.
Glass is a 
Glass is a super cooled liquid.
Which of the following types of forces bind together the carbon atoms in diamond ? 
In diamond each carbon atom is sp 3 hybridized and thus forms covalent bonds with four other carbon atoms lying at the corners of a regular tetrahedron.
Water gas is produced by 
Water gas is made by blowing steam through the layer of incandescent coal.
Which of the following elements is extracted commercially by the electrolysis of an aqueous solution of its compound ? 
Chlorine is prepared commercially by the electrolysis of an aqueous solution of sodium chloride. It is mainly used as a bleaching agent, bacteriocide and an industrial chemical.
Which of the following statements about H3BO3 is not correct ? 
H3BO3 is a weak monobasic acid.
In graphite, electrons are 
In graphite, each carbon is sp2 -hybridized and the single occupied unhybridized porbitals of C-atoms overlap side wise to give π -electron cloud which is delocalized and thus the electrons are spread out between the structure.
Glass reacts with HF to produce 
The correct answer is option B
Common glass consists of silica (SiO2). When HF reacts with silica it will form H2SiF6 or SiF4. Both can soluble in water which means that a fresh surface of SiO2 will be exposed to attack by HF.
In borax bead test which compound is formed?
Which one of the following statements about the zeolites is false ? 
Zeolites are aluminosilicates having three dimensional open structure in which four or six membered rings predominates. Thus, due to open chain structure, they have cavities and can take up water and other small molecules.
Al2O3 can be converted to anhydrous AlCl3 by heating 
Al2O3 can be converted to anhydrous AlCl3 by heating a mixture of Al2O3 and carbon in dry Cl2
The straight chain polymer is formed by:
Hydrolysis of substituted chlorosilanes yield corresponding silanols which undergo polymerisation.
Polymerisation of dialkyl silandiol yields linear thermoplastic polymer.
The tendency of BF3, BCl3 and BBr3 to behave as Lewis acid decreases in the sequence
A molecule is said to be a lewis acid if it can accept a lone pair.
When the halide is more electronegative the interelectronic repulsion increases making the molecule difficult to accept a lone pair.
Size of halide also behaves in the same way. Also the degree of hydrolysis increases from fluorine to iodine,so the lewis acidic character increases in the same order.
So,the order of lewis acidity is BBr3 > BCl3 > BF3.
Name the type of the structure of silicate in which one oxygen atom of [SiO4]4– is shared ? 
Aluminium is extracted from alumina (Al2O3) by electrolysis of a molten mixture of : 
Fused alumina (Al2O3) is a bad conductor of electricity. Therefore, cryolite (Na3AlF6) and fluorspar (CaF2) are added to purified alumina which not only make alumina a good conductor of electricity but also reduce the melting point of the mixture to around 1140 K.
Which of the following structure is similar to graphite? [NEET 2013]
Boron nitride (BN) is known as inorganic graphite. The most stable form is hexagonal one. It has layered structure similar to graphite.
Which of these is not a monomer for a high molecular mass silicone polymer? [NEET 2013]
Since Me3SiCl contains only one Cl, therefore it can’t form high molecular mass silicon polymer. It can form only dimer.
The basic structural unit of silicates is : [NEET 2013]
SiO44– is basic structural unit of silicates.
Which statement is wrong? [NEET Kar. 2013]
Feldspars are 3-dimensional aluminosilicates.