According to the Periodic Law of elements, the variation in properties of elements is related to their

The atomic numbers of Vanadium (V), Chromium (cr), Manganese (Mn) and Iron (Fe), respectively, $$23,24,25$$ and $$26$$. Which one of these may be expected to have the higher second ionization enthalpy?

Which one of the following is an amphoteric oxide?

The reduction in atomic size with increase in atomic number is a characteristic of elements of

Which one of the following process will produce hard water?

Which of the following could act as a propellant for rockets?

How many unit cells are present in a cubeshaped ideal crystal of NaCl of mass 1.00 g? [Atomic masses: Na = 23, Cl = 35.5]

Bottles containing C6H5l and C6H5CH2I lost their original labels. They were labelled A and B for testing A and B were separately taken in test tubes and boiled with NaOH solution. The end solution in each tube was made acidic with dilute HNO3 and then some AgNO3 solution was added. Substance B gave a yellow precipitate. Which one of the following statements is true for this experiment?

The half-life of a radioactive isotope is three hours. If the initial mass of the isotope were 256 g, the mass of it remaining undecayed after 18 hours would be

In respect of the equation k = Ae-Ea/RT in chemical kinetics, which one of the following statements is correct?

The rate law for a reaction between the substances A and B is given by Rate = k[A]n [B]m On doubling the concentration of A and halving the concentration of B, the ratio of the new rate to the earlier rate of the reaction will be as

For the reaction system: 2NO(g) + O2(g) $$\to$$ 2NO2(g) volume is suddenly reduce to half its value by increasing the pressure on it. If the reaction is of first order with respect to O2 and second order with respect to NO, the rate of reaction will

The radionucleide $${}_{90}^{234}Th$$ undergoes two successive $$\beta$$ -decays followed by one $$\alpha$$-decay. The atomic number and the mass number respectively of the resulting radionucleide are

Which one of the following characteristics is not correct for physical adsorption?

An ethar is more volatile than an alcohol having the same molecular formula. This is due to

During dehydration of alcohols to alkenes by heating with conc. H2SO4 the initiation step is

Concentrated hydrochloric acid when kept in open air sometimes produces a cloud of white fumes. The explanation for it is that :

Glass is a :

What may be expected to happen when phosphine gas is mixed with chlorine gas?

Graphite is a soft solid lubricant extremely difficult to melt. The reason for this anomalous behaviour is that graphite :