The rate constants of a reaction at 200 K and 300 K are \(0.02 s^{-1}\) and \(0.04 s^{-1}\). The activation energy ( \(E _{ a }\) ) for this reaction will be :

Calculate the magnetic moment (spin-only) of a trivalent ion in aqueous solution if its atomic number is 22 .

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Nearly all the transition elements display typical metallic properties such as high tensile strength, ductility, malleability, high thermal and electrical conductivity and metallic lustre. The transition metals (with the exception of Zn, Cd and Hg) are very hard and have low volatility. Their melting and boiling points are high. They have high enthalpies of atomization. lons of the same charge in a given series show progressive decrease in radius with increasing atomic number. However, the variation within a series is quite small. The filling of 4f before 5d orbital results in a regular decrease in atomic radii called Lanthanoid contraction which essentially compensates for the expected increase in atomic size with increasing atomic number. The net result of the lanthanoid contraction is that the second and the third d series exhibit similar radii (e.g., Zr 160 pm, Hf 159 pm) and have very similar physical and chemical properties. There is an increase in ionisation enthalpy along each series of the transition elements from left to right. The first ionisation enthalpy, in general, increases, but the magnitude of the increase in the second and third ionisation enthalpies for the successive elements, is much higher along a series. One of the notable features of a transition elements is the great variety of oxidation states these may show in their compounds.
Atomic number of Fe, Co, Ni and Cu are 26, 27, 28 and 29 respectively. Which among them is expected to possess the highest value for the second ionization enthalpy?

The correct IUPAC name for the following structure is:

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A colloid is a heterogeneous system in which a substance is dispersed (dispersed phase) as fine particles in another substance called dispersion medium.
Their particle size is intermediate between that of pure solutions (less than 1 nm ) and suspensions (greater than 1000 nm ).
They are known for interesting properties such as enormous surface area, Tyndall effect, Brownian motion etc.
They are widely used in industries and day to day life.
Some prominent uses of colloids are those in smoke precipitators, purification of water, medicines, cleansers etc.
Stability of a colloid is intermediate between that of a solution and suspension. This stability can be attributed to _____________
A. Presence of charge on the particles of dispersed phase.
B. Prolonged mechanical stirring.
C. Solvation by the dispersion medium.
D. Brownian Motion.
E. Dialysis
Choose the correct answer from the options given below :

Two isomeric compounds, A: \([\text{Co}(\text{NH}_3)_5\text{Cl}]\text{SO}_4\) and B: \([\text{Co}(\text{NH}_3)_5(\text{SO}_4)]\text{Cl}\)
can be distinguished using which of the following?

In the formation of a Leclanche cell, the space between electrodes is filled with:
(A) \(ZnCl _2\)
(B) \(NH _4 Cl\)
(C) \(AlCl _3\)
(D) ZnS
(E) \(NH _4 NO _3\)
Choose the correct answer from the options given below :

Which one of the following regions is called as "lungs of the planet"?

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There are some deposits of nitrates and phosphates in the earth’s crust. Nitrates are more soluble in water. Nitrates are difficult to reduce under laboratory conditions, but microbes do it easily. Ammonia forms a large number of complexes with transition metals. Hybridisation easily explains the ease of sigma donation capability of NH₃ and PH₃. Phosphine is an inflammable gas, prepared from white phosphorus.
Which of the following is the correct statement?
A. Between NH₃ and PH₃, NH₃ is a better electron donor because the lone pair of electrons occupy spherical 's' orbital and is less directional.
B. Between NH₃ and PH₃, NH₃ is a better electron donor because the lone pair of electrons occupies sp³ orbital and is more directional.
C. Between NH₃ & PH₃, PH₃ is a better electron donor because the lone pair of electrons occupies sp² orbital and is more directional.
D. Between NH₃ & PH₃, PH₃ is a better electron donor because the lone pair of electrons occupies 's' orbital and is less directional.
Choose the most appropriate answer from the options given below:

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DNA Fingerprinting
Polymorphism in DNA sequence is the basis of genetic mapping of the human genome as well as of DNA fingerprinting. DNA fingerprinting involves identification of differences in some specific regions in the DNA sequence called repetitive DNA. It works on the principle of polymorphisms in DNA sequences. The repetitive DNA are separated from bulk genomic DNA. The bulk DNA forms a major peak and the other small peaks are referred to as satellite DNA. These repetitive/satellite DNA sequences show a high degree of polymorphisms and form the basis of DNA fingerprinting.
One of the most frequently used techniques in DNA fingerprinting is

The capacity to generate a whole plant from any explant is called:

Radiation of frequency \(2 v_0\) incident on a metal with threshold frequency \(v_0\) results in maximum kinetic energy of photoelectrons as :

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Secondary treatment or biological treatment: The primary effluent is passed into large tanks where air is pumped into it. This allows vigorous growth of aerobic microbes. While growing, these microbes consume the major part of the organic matter in the effluent. This significantly change the BOD (biochemical oxygen demand) of the effluent. The effluent in then passed into a tank a small part of the sludge is pumped back into the aeration tank to serve as the inoculum. The remaining major part of the sludge is pumped into large tanks called sludge digesters. Here, other kinds of bacteria grow anaerobically in the sludge. The biogas produced can be used source of energy as it is inflammable. The effluent from the secondary treatment plant is generally released into natural water bodies like rivers and streams.
The biogas is a mixture of the following gases