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borax bead test is used to identify the nature of cation present in solution by observing the colour of bead. the colour and bead of copper formed during its borax bead test in hot oxidising flame is

Boric anhydride is a non-flammable substance. When it reacts with a coloured metallic salt, it produces a distinctive coloured metal metaborate... View Article

0.1 mol of ideal gas compressed reversibly isothermally from 10 l to 1 l at 100 k. the work done in the process is

It is a reversible & isothermal process. n = 0.1 molP1 = 1P2 = 10T = 100 Work done = -nRT ln (P1/P2)= -(0.1) x 8.314 x 100 x ln(1/10)= +... View Article

the correct order of bond lengths for c–c bonds in benzene, ethyne, ethene and ethane is

One sigma and one pi bond are found in alkene bonds. One sigma and one pi bond are also found in benzene. In the case of benzene, however, the pi... View Article

one mole of hydrogen gas at temperature t is mixed with one mole of helium gas at temperature 2t in an isolated vessel. the equilibrium temperature of the gas mixture is

△Q = nCp△T (Cp)m = [1 x (5R/2) + (1x7R/2)]/2 = 12R/4 = 3R △Q = 2 x 3R x (100-0) △Q = 2 x 3 x 2 x 100 △Q = 1200cal... View Article

a gaseous mixture of equal mass of ch4 and o2 is stored over water. if total pressure is 0.5 atm then partial pressure of dry ch4 gas is (aqueous tension = 0.2 atm)

Molecular Mass of CH4=16 Moles of CH4 = x/16 Molecular Mass of O2=32 Moles of O2 = x/32 Total moles = (x/16) + (x/32) = 3x/32 Mole fractions of... View Article

which among the following pairs has bleaching action due to theIRR reducing and oxidising property respectively?

SO2 and Cl2 pairs has bleaching action. Sulfur dioxide and chlorine are both effective bleaching agents. Chlorine's bleaching action is based on... View Article

number of isomeric alcohol(s) with molecular formula c5h12o which will give positive iodoform test is

There are 8 alcohol possible for c5h12o molecule. They are 1-pentanol 2-pentanol 3-pentanol 2-methylbutan-1-ol 2-methylbutan-2-ol... View Article

time+required+for+75%+radioactive+disintegration

1st half- Life → 50% decay 2nd half- Life → 75% decay The half-life period of the radioactive element, if 75% of it disintegrates in 40 min, is... View Article

at equilibrium the rate of dissolution of a solid solute in a volatile liquid solvent is

We can say that at equilibrium, the rate of dissolution is the forward reaction and the rate of crystallisation is the backward reaction. For a... View Article

if 2.8 g of a metal oxide contains 0.8 g oxygen, then the equivalent mass of the metal is

According to the law of definite proportion, a given compound always has the same proportion of constituents by weight. Case I 2.8 g of CaO... View Article

solubility of cu(oh)2 in 0.1 m aqueous naoh solution is (ksp of cu(oh)2 = 2.2 × 10–20)

For Cu(OH)2, the expression of solubility product is: Ksp = [Cu2+][OH-]2 = (s)(2s)2 = 4s3 Substitute Ksp = 1.6 × 10–19 in the above equation.... View Article

the correct set of carbonate ores is (i) dolomite (ii) anglesite (iii) cuprite (iv) malachite (v) argentite (vi) siderite

Magnesite − MgCO3 Siderite − FeCO3 are the correct set of carbonate ore.... View Article

100 ml of 0.2 m alcl3 is required just to cause coagulation of 700 ml of as2s3 sol. what is the flocculation value of alcl3?

Flocculation, also known as coagulation is the process of precipitation of a colloidal solution by the addition of the excess of an electrolyte.... View Article

reema took 5 ml of lead nitrate solution in a beaker and added approximately 4 ml of potassium iodide solution to it. what would she observe?

The relation between lead nitrate and potassium iodide is an example of precipitation reaction. Pb(No3)2 + 2KI ⟶ PbI2 + 2KNO3 (yellow ppt) The... View Article

a radioactive substance has activity 2a0 at t = 0. after 3 second it has activity a0. the decay constant of the sample is

t=0 activity is N0 then after time t the activity is given as 100=1600×(1/2)^n so n=4 n=4 and t=8s we get t1/2 = 2s So activity after 2 seconds... View Article

one mole of n2o4 in a 1l flask decomposes to attain the equilibrium n2o4(g) ⇌ 2no2(g). at the equilibrium the mole fraction of n2o4 is 1 2 . then kc will be

Mole fraction of NO2=2x/(1−x+2x)=2x/(x+1)=1/2 solving, we get 4x=x+1 3x=1 x=1/3 =(4/9)/(2/3)=4X3/9X2=2/3 Therefore, 2/3 is the answer.... View Article

1 mol of ideal gas expands reversibly and isothermally from 1 l to 100 l at 300 k. the heat exchange during the process is nearly

W = −1×8.314×300×ln 20/10 W = −2494.2×(ln2−ln1) = −1728.8J = −1.73 kJ From first law of... View Article

the gold number of four protective colloids a, b, c and d are 0.1, 0.25, 5 and 15 respectively. the maximum protecting power is of

Smaller the gold number, greater is the protective power. 0.25>0.1>5>15... View Article

a gas mixture consists of 2 moles of nitrogen and 4 moles of xenon at temperature t. neglecting all vibrational modes, the total internal energy of the system is

For Oxygen , no of moles n1=2 , no. Of degree of freedom per molecule, f1=5 For Argon, no.of moles , n2=4 no.of degree of freedom per... View Article

consider the ellingham diagram for zn, mg and carbon converting into theIRR corresponding oxides. at 1100ºc, which one of the following reactions is spontaneous to a maximum extent?

Any metal will reduce the oxide of other metals above it on the Ellingham diagram because the free energy difference will become more negative,... View Article