What is atomic number of an atom?
Which among the following would cause the bright red colur due to bursting of crackers?
Based on lattice energy and other considerations which one of the following alkali metal chlorides is expected to have the highest melting point.
Which of the following sets of quantum numbers is correct for an electron in 4f orbital?
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Which of the following elements behave chemically both as a metal and a non metal?
While tinning of brass utensils, the ammonium chloride powder used to clean the hot utensil produces fumes of:
Consider the following statements and select the correct code.
Assertion (A): The main constituent of the
liquefied petroleum gas is methane.
Reason (R): Methane can be used directly for burning in homes and factories where it can be supplied through pipelines.
Which of the following is the most active chemically?
The structure of diborane (B2H6) contains
Conduction band electrons have more mobility than holes because they are:
Which among the following elemtns are generally find in free state?
Which one among the following elements/ions is essential in small quantities for development of healthy teeth but causes mottling of the teeth if consumed in higher quantities?
Air contains maximum amount of
The number of electrons presents in H+ is:
The method that cannot be used for removing permanent hardness of water is:
The credit of construction of first nuclear reactor goes to -
Which one of the following types of drugs reduces fever?
To which orbitals may an electron in a 2p orbital in a hydrogenic atom make allowed spectroscopic transitions?
Which of the following atmospheric gases constitute greenhouse gases?
(1) Carbon dioxide (2) Nitrogen
(3) Nitrous oxide (4) Water vapour
Select the correct answer using the codes given below:
Lattice energy of an ionic compounds depends upon:
Which metal is heaviest ?
Which of the following is/are not correctly matched?
(I) Absolute alcohol – 100% ethanol
(II) Power alcohol – 90 – 95% ethanol
(III) Rectified spirit – 5% ethanol
What is the role of ultraviolet (UV) radiation in the water purification system?
(1) It inactivates / kills the harmful micro- organisms in water.
(2) It removes all the undesirable odours from the water.
(3) It quickens the sedimentation of solid particles and improves the clarity of water.
Which of the statements given above is/are correct?
The shortest wavelength f X-rays emitted from an X-ray tube depends on:
The ore which is found in abundance in India is ?
During the process of electrolytic refining of copper, some metals present as impurity settle as ‘anode mud’ These are:
If the star can convert all the He nuclei completely into oxygen nuclei, the energy released per oxygen nucleus is (Mass of He nucleus is 4.0 026 amu and mass of oxygen nucleus is 15.9994 amu):