100 mL of a water sample contains 0.81 g of calcium bicarbonate and 0.73 g of magnesium bicarbonate. The hardness of this water sample expressed in terms of equivalents of CaCO3 is: (molar mass of calcium bicarbonate is 162 g mol-1 and magnesium bicarbonate is 146 g mol-1)
1,000 ppm
100 ppm
10,000 ppm
5000 ppm
The correct order of hydration enthalpies of alkali metal ions is:
Li+ > Na+ > K+ > Cs+ > Rb+
Na+ > Li+ > K+ > Rb+ > Cs+
Na+ > Li+ > K+ > Cs+ > Rb+
Li+ > Na+ > K+ > Rb+ > Cs+
Assertion : Ozone is destroyed by CFCs in the upper stratosphere.
Reason : Ozone holes increase the amount of UV radiation reaching the earth.
Assertion and reason are incorrect.
Assertion is false, but the reason is correct.
Assertion and reason are correct and the reason is the correct explanation for the assertion.
Assertion and reason are correct, but the reason is not the explanation for the assertion.
Which is wrong with respect to our responsibility as a human being to protect our environment ?
Avoiding the use of floodlighted facilities
Setting up compost tin in gardens
Restricting the use of vehicles
Using plastic bags
For the reaction 2A + B → C, the values of initial rate at different reactant concentrations are given in the table below. The rate law for the reaction is :
[A] (mol L-1) | [B] (mol L-1) | Initial rate (mol L-1 s-1) |
0.05 | 0.05 | 0.045 |
0.10 | 0.05 | 0.090 |
0.20 | 0.10 | 0.72 |
Rate = k[A]2[B]2
Rate = k[A]2[B]
Rate = k[A][B]
Rate = k[A][B]2
Adsorption of a gas follows Freundlich adsorption isotherm. x is the mass of the gas adsorbed on mass m of the adsorbent. The plot of log versus log p is shown in the given graph. is proportional to :
p3/2
P3
P2
P2/3
With respect to an ore, Ellingham diagram helps to predict the feasibility of its
Thermal reduction
Electrolysis
Zone refining
Vapour phase refining
A.
Thermal reduction
Ellingham diagrams are related to the values for the formation of oxides and can be used for the thermal reduction of ores.
Element ‘B’ forms ccp structure and ‘A’ occupies half of the octahedral voids, while oxygen atoms occupy all the tetrahedral voids. The structure of bimetallic oxide is:
AB2O4
A2B2O
A2BO4
A4B2O