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.
(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.
(c) both have similar atomic radius.
Explanation: Zirconium (Zr) and hafnium (Hf) have similar atomic radius hence they show similar physical and chemical properties.
Explanation: Zirconium (Zr) and hafnium (Hf) have similar atomic radius hence they show similar physical and chemical properties.
Suggest reasons for the following features of transition metal chemistry :
(i) The transition metals and their compounds are usually paramagnetic.
(ii) The transition metals exhibit variable oxidation states.
(i) Give reasons for the following :
(a) Compounds of transition elements are generally coloured.
(b) MnO is basic while Mn₂O₇ is acidic.
(ii) Calculate the magnetic moment of a divalent ion in aqueous medium if its atomic number is 26.
When KMnO₄ solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because
(a) CO₂ is formed as the product.
(b) The reaction is exothermic.
(c) MnO₄⁻ catalyses the reaction.
(d) Mn²⁺ acts as an auto-catalyst.
Describe the preparation of potassium permanganate. How does the acidified permanganate solution react with oxalic acid ?
Write the ionic equations for the reactions.
Explain the following :
(i) The enthalpies of atomization of transition metals are quite high.
(ii) The transition metals and many of their compounds act as good catalysts.
Explain the following observations:
(i) Copper atom has completely filled d orbitals (3d¹⁰) in its ground state, yet it is regarded as a transition element.
(ii) Cr²⁺ is a stronger reducing agent than Fe²⁺ in aqueous solution.
The correct order of the packing efficiency in different types of unit cells is ________.
(A) fcc < bcc < simple cubic
(B) fcc > bcc > simple cubic
(C) fcc < bcc > simple cubic
(D) bcc < fcc = simple cubic
Electronic configuration of a transition element X in +3 oxidation state is [Ar]3d⁵. What is its atomic number?
(a) 25
(b) 26
(c) 27
(d) 24
Low concentration of oxygen in the blood and tissues of people living at high altitude is due to-
(a) low temperature
(b) low atmospheric pressure
(c) high atmospheric pressure
(d) both low temperature and high atmospheric pressure
Which of the following is an example of vic-dihalide?
(a) Dichloromethane.
(b) 1,2-dichloroethane.
(c) Ethylidene chloride.
(d) Allyl chloride.
In the periodic table of the elements, the phrase “middle row anomaly” refers to
a) Middle elements of periodic table are transition metals.
b) Middle element of each group is unstable.
c) the relative instability of bromine oxides compared to the other halogen oxides.
d) The higher oxides of halogens tend to be more stable than the lower ones.
Which of the following reagents cannot, be used to oxidise primary alcohols to aldehydes?
(a) \(CrO_3\) in anhydrous medium.
(b) \(KMnO_4\) in acidic medium.
(c) Pyridinium chlorochromate.
(d) Heat in the presence of Cu at 573 K.
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.