Test Preparation on IIT JEE Mains Mock Test-15

CHEMISTRY
For detection of Phosphorus in an organic compound, the white-colored precipitate formed is of :

1
(NH_d)3PO₄.12MoO₃
2
MgNH₄PO₄
3
Mg₂P2O₇
4
Mo(POd)₃

P + 3H + 4O → H3PO4
H3PO4 + Magnesia powder → MgNH4PO4\
2MgNH4PO4 → Mg2P2O7 + 2NH3 + H2O
White ppt

The polymer commonly used in the manufacture of unbreakable plastic crockery is made from :

1Melamine and formaldehyde
2phenol and formaldehyde
3ethylene glycol and phthalic acid
4ethylene glycol and terephthalic acid

Melamine resin or melamine formaldehyde (also shortened to melamine) is a hard, thermosetting plastic material made from melamine and formaldehyde by polymerization

A pan containing a liquid (b.pt.127oc) is placed over a strong flame capable of heating up to 600oC. Which of the following statements is correct about the liquid?

1Temperature of boiling liquid can rise above 127oC during boiling.
2Average K.E. of liquid molecules will increase during boiling.
3Temperature of boiling liquid will remain 127oC.
4All the above are correct.

The standard heat of formation of a compound is the enthalpy change for :

1formation of 1 mol. of a substance at NTP.
2formation of 1 mol of a substance at OoC and 1 atm. pressure from its elements.
3formation of 1 mol of a substance at 298 K and 1 atm. pressure from its elements
4formation of 1 mol of a substance in any reaction at 298K and 1 atm. pressure.

The standard heat of formation of a compound is the enthalpy change for the formation of 1 mole of a substance at 298 K and 1 atm. pressure from its elements.

Point out wrong statement :

1wave function ￥ can have positive as well as negative values.
2￥2 has positive values only.
33sorbital has two nodes in it.
4￥ give probability of finding an electron around the nucleus.

￥² gives probability of finding an electron around the nucleus.

An aqueous solution of NaCl containing 5.85 g.NaCl in 105.85 g. of solution will freeze at about (Kf for water =1.86 Km-a) :

11.86°C
23.72°C
31.86°C
43.72°C

Weight of NaCl (w2)= 5.8 g weight of water (w1) = 105.85 – 5.85 = 100; Kf for water =1.86 Km-1 ΔTf = i x Kf x m = i x kf w2/m2x1000/w1=

2x1.86x5.85/58.5x1000/100=3.72

In paper chromatography:

1mobile phase is liquid and the stationary phase is solid.
2mobile phase is solid and the stationary phase is liquid
3mobile phases is liquid and the stationary phase is a thin liquid film adsorbed on the paper.
4both mobile and stationary phases are solids.

Paper chromatography is a technique that is used to separate and to identify components of a mixture. In this technique, the sample mixture is applied to a piece of filter paper, the edge of the paper is immersed in a solvent, and the solvent moves up the paper by capillary action. This is a partition chromatography in which the substances are distributed or partitioned between two liquid phases. One phase is the water which is held in pores of filter paper used and other phase is that of mobile phase which moves over the paper.

An antigen is :

1small fragment of a antibiotic
2a steroidal hormone
3a foreign molecule that while entering an organism induces certain responses
4a drug taken against a particular allergy.

An antigen is a substance that evokes the production of one or more antibodies.

What is a vat dye ?

1A dye that can be applied directly on a fibre sample taken in vat.
2A colourless compound in the reduced state and coloured in the oxidised state.
3Dye that can be applied only to fibres.
4Dye that changes the colour with the change in pH of solution.

The term vat dye is used to describe a chemical class of dyes that are applied to cellulosic fibre (ie cotton) using a redox reaction. The dye is soluble only in its reduced (oxygen-free) form. The fibre is immersed repeatedly in this oxygen-free dyebath, and then exposed to the air, whereupon the water-soluble reduced form changes colour as oxygen turns it to the water-insoluble form.


Right Ans	Wrong Ans	Not Attempted

CHEMISTRYFor detection of Phosphorus in an organic compound, the white-colored precipitate formed is of :