What is used to avoid melting of ice ?
The Pauling electronegativities of fluorine and chlorine are 4.0 and 3.0 respectively. Estimate the dipole moment of chlorine monofluoride, ClF.
Reactive metals are extracted by ______________.
Chemical used in photography is:
Living in the atmosphere of CO is dangerous because it:
The metal used to recover copper from a solution of copper sulphate is ?
Which among the following oxides cause the Acid rain ?
The luster of a metal is due to :
What is the most common isotope of hydrogen?
What do non metal atoms lose to form negatively charged ions?
The number and type of bonds between two carbon atoms in calcium carbide are:
The graphite rods in the nuclear reactor:
Imagine an atom made p of proton and a hypothetical particle of double the mass of the electron but having he same charge as the electron. Apply the Bohratom model and consider all posible transitions of this hypothetical particle to the first excited level. The longest waveength photon that will be emitted has wavelength λ (given in terms of the Rydberg constant R for the hydrogen atom) equal to:
Which one of the following is the softest?
The credit of construction of first nuclear reactor goes to -
The electron in a hydrogen atom makes a transition from an excited state of state the ground Which of the following statements is true ?
Zone refining is used for the purification of:
Which of the following elements behave chemically both as a metal and a non metal?
The partial pressure of a component in a gas-phase reaction is 0.452 atm. What is the activity of the component?
The inexhaustible source of energy of the stars is due to:
Unreactive non metals are called. ____________ .
Conduction band electrons have more mobility than holes because they are:
The term PVC used in the plastic industry stands for:
A freshly prepared radioactive source of half life 2 hr emits radiation of intinsity which is 64 times the permissible safe level. The minimum time after possible to work safely with this source is when it would be:
The number of electrons presents in H+ is:
2 methylbutane on reacting with bromine in the presence of sunlight gives mainly:
Consider the following statements:
If there were no phenomenon of capillarity
(1) It would be difficult to use a kerosene lamp.
(2) One would not be able to use a straw to consume a soft drink.
(3) The blotting paper would fail to function.
(4) The big trees that we see around would not have grown on the earth.
Which of the statements given above are correct?