Some Basic Concept Of Chemistry

If NAis Avogadro?s number then number of valence electrons in 4.2 g of nitride ions (N3−) A) 2.4 NA B) 4.2 NA C) 1.6NA D) 3.2NA

A

Hydrogen combines with oxygen to form H2O in which 16 g of oxygen combine with 2 g of hydrogen. Hydrogen also combines with carbon to form CH4 in which 2 g of hydrogen combine with 6 g of carbon. If carbon and oxygen combine together then they will do show in the ratio of A) 6 : 16 or 12 : 32 B) 6 : 18 C) 1 : 2 D) 12 : 24

A

In known elements, the maximum number is of [CPMT 1985] A) Metals B) Non-metals C) Metalloids D) None of these

A

In the reaction 2Na2S2O3+I2→Na2S4O6+2NaI, the equivalent weight of Na2S2O3(mol. wt. = M) is equal to A) M B) M/2 C) M/3 D) M/4

A

on increasing pressure density _____(inc/decrease) thus the molecules will be _____(close/far) from each other leading to ____(inc/dec) in main free path

increases closer decrease

internal energy and pressure of a gas per unit volume are related as

p=2/3E

translatory kinetic energy equation

tr KE=3RT/2

Ratio of Cpand Cvof a gas X is 1.4, the number of atom of the gas ?X? present in 11.2 litres of it at NTP will be [CBSE 1999] A) 6.02×1023 B) 1.2×1023 C) 3.01×1023 D) 2.01×1023

A

Sulphur forms the chloridesS2Cl2 and SCl2. The equivalent mass of sulphur in SCl2is [EAMCET 1985; Pb. CET 2001] A) 8 g/mole B) 16 g/mole C) 64.8 g/mole D) 32 g/mole

A

The vapour density of a gas is 11.2. The volume occupied by 11.2 g of the gas at ATP will be [Bihar CET 1995] A) 11.2 L B) 22.4 L C) 1 L D) 44.8 L

A

With increase of pressure, the mean free path [Pb. CET 1985] A) Decreases B) Increases C) Does not change D) Becomes zero

A

A mixture of ZnCl2 and PbCl2 can be separated by [AFMC 1989] A) Distillation B) Crystallization C) Sublimation D) Adding aceitic acid

B

A mixture of methyl alcohol and acetone can be separated by [Manipal PMT 2001] A) Distillation B) Fractional distillation C) Steam distillation D) Distillation under reduced pressure

B

Equivalent weight of crystalline oxalic acid is [MP PMT 1995] A) 30 B) 63 C) 53 D) 45

B

Given P=0.0030m, Q=2.40m, R=3000m, Significant figures in P,Q and R are respectively [Pb. CET 2002] A) 2, 2, 1 B) 2, 3, 4 C) 4, 2, 1 D) 4, 2, 3

B

Helium atom is two times heavier than a hydrogen molecule at 298 K, the average kinetic energy of helium is [IIT 1982] A) Two times that of a hydrogen molecule B) Same as that of a hydrogen molecule C) Four times that of a hydrogen molecule D) Half that of a hydrogen molecule

B

The equivalent weight of an element is 4. Its chloride has a V.D 59.25. Then the valency of the element is [BHU 1997] A) 4 B) 3 C) 2 D) 1

B

Which one of the following properties of an element is not variable [Bihar MADT 1981] A) Valency B) Atomic weight C) Equivalent weight D) All of these

B

Which one of the following statements is NOT true about the effect of an increase in temperature on the distribution of molecular speeds in a gas [AIEEE 2005] A) The most probable speed increases B) The fraction of the molecules with the most probable speed increases C) The distribution becomes broader D) The area under the distribution curve remains the same as under the lower temperature

B

1.24 gm P is present in 2.2 gm of A) P2S2 B) PS2 C) P4S3 D) P2S4

C

2 g of hydrogen combine with 16 g of oxygen to form water and with 6 g of carbon to form methane. In carbon dioxide 12 g of carbon are combined with 32 g of oxygen. These figures illustrate the law of A) Multiple proportions B) Constant proportions C) Reciprocal proportions D) Conservation of mass

C

74.5 g of a metallic chloride contain 35.5 g of chlorine. The equivalent weight of the metal is [CPMT 1986] A) 19.5 B) 35.5 C) 39.0 D) 78.0

C

Kinetic energy of a gas depends upon its[Bihar MADT 1982] A) Molecular mass B) Atomic mass C) Equivalent mass D) None of these

C

Significant figures in 0.00051 are A) 5 B) 3 C) 2 D) 4

C

The oxide of a metal has 32% oxygen. Its equivalent weight would be [MP PMT 1985] A) 34 B) 32 C) 17 D) 8

C

The sulphate of a metal M contains 9.87% of M. This sulphate is isomorphous with ZnSO4.7H2O. The atomic weight of M is [IIT 1991] A) 40.3 B) 36.3 C) 24.3 D) 11.3

C

Which property of an element is always a whole number [MP PMT 1986] A) Atomic weight B) Equivalent weight C) Atomic number D) Atomic volume

C

1.0 g of an oxide of A contained 0.5 g of A. 4.0 g of another oxide of A contained 1.6 g of A. The data indicate the law of A) Reciprocal proportions B) Constant proportions C) Conservation of energy D) Multiple proportions

D

1.25 g of a solid dibasic acid is completely neutralised by 25 ml of 0.25 molar Ba(OH)2solution. Molecular mass of the acid is A) 100 B) 150 C) 120 D) 200

D

1.520 g of the hydroxide of a metal on ignition gave 0.995 gm of oxide. The equivalent weight of metal is [DPMT 1984] A) 1.520 B) 0.995 C) 19.00 D) 9.00

D

A sample was weighted using two different balances. The result?s were (i) 3.929 g (ii) 4.0 g. How would the weight of the sample be reported A) 3.929 g B) 3 g C) 3.9 g D) 3.93 g

D

If the inversion temperature of a gas is −80oC, then it will produce cooling under Joule-Thomson effect at A) 298 K B) 273 K C) 193 K D) 173 K

D

Which of the following halogen can be purified by sublimation [Manipal PMT 2001] A) F2 B) Cl2 C) Br2 D) I2

D

relation btw vapour density and MW

MW=2*VD