Highest oxidation state of manganese in fluoride is +4 (MnF₄) but highest oxidation state in oxides is +7 (Mn₂O₇) because
(a) fluorine is more electronegative than oxygen.
(b) fluorine does not possess d-orbitals.
(c) fluorine stabilises lower oxidation state.
(d) in covalent compounds fluorine can formsingle bond only while oxygen forms double bond.
(a) fluorine is more electronegative than oxygen.
(b) fluorine does not possess d-orbitals.
(c) fluorine stabilises lower oxidation state.
(d) in covalent compounds fluorine can formsingle bond only while oxygen forms double bond.
(d) in covalent compounds fluorine can form single bond only while oxygen forms double bond.
Give reasons :
(i) Mn shows the highest oxidation state of +7 with oxygen but with fluorine it shows the highest oxidation state of +4.
(ii) Transition metals show variable oxidation states.
(iii) Actinoids show irregularities in their electronic configurations.
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
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.
(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.
Name the following :
(i) A transition metal which does not exhibit variation in oxidation state in its compounds.
(ii) A compound where the transition metal is in the +7 oxidation state.
(iii) A member of the lanthanoid series which is well known to exhibit +4 oxidation state.
(iv) Ore used in the preparation of Potassium dichromate.
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.
Account for the following :
(i) CuCl₂ is more stable than Cu₂Cl₂.
(ii) Atomic radii of 4d and 5d series elements are nearly same.
(iii) Hydrochloric acid is not used in permanganate titration.
Which of the following compounds will be most easily attacked by an electrophile?
The difference between the electrode potentials of two electrodes when no current is drawn through the cell is called ___________.
a. Cell potential.
b. Electromotive Force.
c. Potential difference.
d. Cell voltage.
The sharp melting point of crystalline solids is due to ___________.
(A) a regular arrangement of constituent particles observed over a short distance in the crystal lattice.
(B) a regular arrangement of constituent particles observed over a long distance in the crystal lattice.
(C) same arrangement of constituent particles in different directions.
(D) different arrangements of constituent particles in different directions.
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
RNA and DNA are chiral molecules. Their chirality is due to :
(a) Chiral bases
(b) Chiral phosphate ester units
(c) D-sugar component
(d) L-sugar component.
Consider the figure and mark the correct option.
(a) water will move from side (A) to side (B) if a pressure lower than osmotic pressure is applied on piston (B).
(b) water will move from side (B) to side (A) if a pressure greater than osmotic , pressure is applied on piston (B).
(c) water will move from side (B) to side (A) if a pressure equal to osmotic pressure is applied on piston (B).
(d) water will move from side (A) to side (B) if pressure equal to osmotic pressure is applied on piston (A).