There is a considerable increase in covalent radius from N to P. However, from As to Bi only a small increase in covalent radius is observed. This is due to
a) Increase in number of shells
b) increase in valence electrons
c) increase in ionisation enthalpy
d) the presence of completely filled d and/or f orbitals
a) Increase in number of shells
b) increase in valence electrons
c) increase in ionisation enthalpy
d) the presence of completely filled d and/or f orbitals
d) the presence of completely filled d and/or f orbitals
Why is Helium used in divers' tank but not hydrogen gas?
a) Helium is lighter than hydrogen.
b) Helium is inert to any chemical reactions.
c) Helium is cheaper.
d) Helium is easy to get from market.
The idea that promoted to Bartlett to prepare first ever compound of Noble gases was
a) Low bond dissociation enthalpy of F-F bond in \(F_2\).
b) High bond enthalpy of Xe-F bond.
c) Ionization enthalpies of \(O_2\) and Xe are almost same.
d) None of the above.
Which statement correct about halogens?
a) They are all diatomic and form univalent ions.
b) They are all capable of exhibiting several oxidation states.
c) They are all diatomic and form diatomic ions.
d) They are all reducing agents.
Which of the following statement is false?
a) Radon is obtained from the decay of radium
b) Helium is an inert gas
c) Xenon is the most reactive among the rare gases
d) The most abundant rare gas found in the atmosphere is helium
Stability of hydrides of group 16 elements
a) increases down the group
b) decreases down the group
c) all hydrides are equally stable
d) none of the above
which is not the property of dioxygen gas
a) Dioxygen is a colourless and odourless gas.
b) Dioxygen is paramagnetic.
c) Dioxygen is diamagnetic.
d) Dioxygen is soluble in water which support aquatic life.
The lowest boiling point of helium is due to its
a) Inertness
b) Gaseous nature
c) Weak van der Waals force between atoms
d) electronic configuration
Which base is present in RNA but not in DNA?
(a) Uracil
(b) Cytosine
(c) Guanine
(d) Thymine
Looking at the setup of an electrochemical cell, what happens when \(E_{ext}\) > 1.1 V
The electronic configuration of Cu(II) is 3d⁹ whereas that of Cu(I) is 3d¹⁰. Which of the following is correct?
(a) Cu(II) is more stable
(b) Cu(II) is less stable
(c) Cu(I) and Cu(II) are equally stable
(d) Stability of Cu(I) and Cu(II) depends on nature of copper salts
One mole of ethyl acetate on treatment with an excess of \(LiAlH_4\) in dry ether and subsequent acidification produces
(a) 1 mole acetic acid + 1 mole ethyl alcohol.
(b) 1 mole ethyl alcohol + 1 mole methyl alcohol.
(c) 2 moles of ethyl alcohol.
(d) 1 mole of 2-butanol.
When Xe reacts with Fluorine in 1:5 ratio at 873 K it forms
a) \(XeF_2\)
b) \(XeF_4\)
c) \(XeF_6\)
d) \(XeOF_4\)
The order of reactivity of the following alcohols with halogen acids is
Although Zirconium belongs to 4d transition series and Hafnium to 5d transition series even then they show similar physical and chemical properties because
(a) both belong to d-block.
(b) both have same number of electrons.
(c) both have similar atomic radius.
(d) both belong to the same group of the periodic table.