Which one of the following groupings represents a collection of isoelectronic species?
Following statements regarding the periodic trends of chemical reactivity of the alkali metals and the halogens are given. Which of these statements gives the correct picture?
The increasing order of the first ionisation enthalpies of the elements B, P, S and F (lowest first) is
Which one of the following ions has the highest value of ionic radius?
Based on lattice energy and other considerations which one of the following alkali metal chlorides is expected to have the highest melting point?
Which among the following factors is the most important in making fluorine the strongest oxidising agent?
Lattice energy of an ionic compound depends upon
According to the periodic law of elements, the variation in properties of elements is related to their
Which is the correct order of atomic sizes?
(At. Nos. : Ce = 58, Sn = 50, Yb = 70 and Lu = 71)
The vapour pressure of water at 20°C is 17.5 mm Hg. If 18 g of glucose (C6H12O6) is added to 178.2 g of water at 20°C, the vapour pressure of the resulting solution will be
Equimolal solutions in the same solvent have
Two solutions of a substance (non electrolyte) are mixed in the following manner. 480 ml of 1.5 M first solution + 520 mL of 1.2 M second solution. What is the molarity of the final mixture?
Benzene and toluene form nearly ideal solutions. At 20°C, the vapour pressure of benzene is 75 torr and that of toluene is 22 torr. The partial vapour pressure of benzene at 20°C for a solution containing 78 g of benzene and 46 g of toluene in torr is
To neutralise completely 20 mL of 0.1 M aqueous solution of phosphorous acid (H3PO3), the volume of 0.1 M aqueous KOH solution required is
6.02 × 10^20 molecules of urea are present in 100 ml of its solution. The concentration of urea solution is
If liquids A and B form an ideal solution, the
25 ml of a solution of barium hydroxide on titration with a 0.1 molar solution of hydrochloric acid gave a litre value of 35 ml. The molarity of barium hydroxide solution was
In a 0.2 molal aqueous solution of a weak acid HX, the degree of ionization is 0.3. Taking Kf for water as 1.85, the freezing point of the solution will be nearest to
Freezing point of an aqueous solution is (–0.186)°C. Elevation of boiling point of the same solution is K b = 0.512°C, K f = 1.86°C, find the
increase in boiling point.
An organic liquid with sweet smell and b.pt 78°C contains C, H and O. On heating with conc. H2SO4 gives a gaseous product (B) of empirical formula (CH2)n. Compound (B) decolourises bromine water and alk. KMnO4. (B) also reacts with one mole of H2 in presence of Ni. What are (A) and (B)?
Sulphanilic acid although has acidic as well as basic group, it is soluble in alkali but insoluble in mineral acid
Although both polymers are prepared by free radical processes, poly (vinyl chloride) is amorphous and poly (vinylidene chloride) (saran) is highly crystallilne. How do you account for the different? (vinylidene chloride is 1,1- dichloroethene).
Treatment of (+)– glucose with HIO4 gives results that confirm its aldohexose structure. What product should be formed, and how much HIO4 should be consumed?
Consult internet and find out how to make orally active protein pharmaceutical. What is the major problem to be encountered?
Does our blood have proteases and nucleases
Find out from internet what is golden rice.
Can you suggest a method to remove oil (hydrocarbon) from seeds based on your understanding of rDNA technology and chemistry of oil?
Diagrammatically represent the experimental steps in cloning and expressing an human
gene (say the gene for growth hormone) into a bacterium like E. coli ?
Diagrammatically represent the experimental steps in cloning and expressing an human
What is gene therapy? Illustrate using the example of adenosine deaminase (ADA) deficiency.
What are Cry proteins? Name an organism that produces it. How has man exploited this
protein to his benefit?
Compare and contrast the advantages and disadvantages of production of genetically modified crops.
What are transgenic bacteria? Illustrate using any one example.
Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because −
(a) bacteria are resistant to the toxin
(b) toxin is immature:
(c) toxin is inactive:
(d) bacteria encloses toxin in a special sac.
In which case of mixing of a strong acid and a base each of 1 N concentration, temperature increase is highest.
The heat of combustion of carbon is 394 kJ. The heat evolved in combustion of 6.023 *10^22 atoms of carbon is
The difference between the heat of reaction of constant pressure and constant volume for the reaction
The heat of neutralisation of HCl by NaOH is –12.1 kJ/mole, the energy of dissociation of HCN is
The dissociation energy of CH4 and C2H6 are respectively 360 & 620 k. cal/mole. The bond energy of C–C is
The heat of combustion of propane C3H8(g) is 
= –2280 kJ /mol. For the combustion of 1.00 m3 of C3H8(g) measured at 25° C annd 1 atm pressure, =
The heat of combustion of CS2 is –3.24 kcal. For the reaction,
If the enthalpy of vaporistion for water is 186.5 kJ/mol, its entropy of vaporistion will be
If 
for a reaction then:
Calculate the maximum work done by the system when 2 mole of ideal gas expands from 2.4 dm3 to 5.6 dm3 at 10°C reversibly. Also calculate the heat change. Repeat the above calculations at 110°C.
How do biofertilisers enrich the fertility of the soil?
Arrange the following in the decreasing order (most important first) of their importance, for the welfare of human society. Give reasons for your answer. Biogas, Citric acid, Penicillin and Curd
Find out the role of microbes in the following and discuss it with your teacher.
(a) Single cell protein (SCP)
(b) Soil
Three water samples namely river water, untreated sewage water and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labelled A, B and C; but the laboratory attendant did not note which was which. The BOD values of the three samples A, B and C were recorded as 20mg/L, 8mg/L and 400mg/L, respectively. Which sample of the water is most polluted? Can you assign the correct label to each assuming the river water is relatively clean?
Microbes can be used to decrease the use of chemical fertilisers and pesticides. Explain how this can be accomplished.