Identify the incorrect statement about halogens.
(A) `F_(2)` is the best oxidant & non metal with highest S.R.P value
(B) The only halogen that oxidises water is `Cl_(2)`
(C) The halogen that occurs in liquid state at `25^(@)C` is `Br_(2)`
(D) Among all halogens `I_(2)` having strong Vander waals forces among its molecules.

Which of the statement is/are true about the reactivity of halogenation of alkanes ? The reactivity ordar is F_(2) gt C1_(2) gt Br_(2) gt I_(2) . I. Lower the activation energy for the chain initiation step, more reactive is the halogen. II. Lower the activation energy for the first chain propagation step, more reactive is the halogen. III. More negative is the overall heat of the reaction (Delta H_(r)^(@)) of halogenation ofg alkane, more reactive is the halogen. IV. Lower the activation energy for the second chain-propagation step, more reactives is the halogen.

Which orbital has only positive value of wave function at all distances from the nucleus : (a)1s (b)2s (c)3p (d)3d

Statement-1: All halogens are coloured. Statement-2: Halogens exist in diatomic gaseous state. Statement-3: F_(2) is more reactive than Cl_(2)

(a) Complete the following chemical equations for reactions : (i) MnO_(4(aq))^(-) + S_(2)O_(3(aq))^(2-) + H_(2)O_((l)) to (ii) Cr_(2)O_(7 (aq))^(2-) + H_(2)S_((g)) + H_((aq))^(+) to (b) Give an explanation for each of the following observations : (i) The gradual decrease in size (actinoid contraction) from element to element is greater among the actinoids than that among the lanthanoids (lanthanoid contraction.) (ii) The greatest number of oxidation states are exhibited by the members in the middle of a transition series. (iii) With the same d-orbitals configuration (d^(4)) Cr^(2+) ion is a reducing agent but Mn^(3+) ion is an oxidising agent .

Each question has four choices, a,b,c and d,out of which only one is correct. Each question contains STATEMENT 1 and STATEMENT 2. if both the statements are true and statement 2 is the correct explanation of statement 1. If both the statements are true but statement 2 is not the correct explanation of statement 1. If statement is True and statement2 is false. If statement1 is false and statement2 is true. Statement 1: If x in [1,sqrt(3)], then the range of f(x)=tan^(-1)x is [pi/4,pi/3] Statement 2 : If x in [a , b], then the range of f(x)i s[f(a),f(b)]dot

The force of interaction between the molecules of same substance is called cohesive force hile force of interaction between molecules of different substances is called adhesive force . Both the forces are attracive and have a range of about 10 A . If we consider a molecule . A well inside a liquid we find that it is equally attracted by the surrounding molecules in all the directions ( with a sphere of radius 10 Å ) and so it does not experience any resultant force . On or near the surface of a liquid , the molecules do not exist on the free side and so a molecule ( say B ) experiences a resultant force vertically downwards into the liquid . For this reason , the molecules of the surface have a tendency to go into the liquid . Thus , the surface tends to contract and gives rise to surface tension . As surface molecules like B experience a net downward force of cohension and have tendency to go down , so in increasing the area of the surface more molecules are to be shifted to the surface from inside . Thus , more mechnical work will have to be done against the net downward force of cohension . This work is stored by the molecules in the surfaces as potential energy called free surface energy . Furthermore , molcules like P , in contact with the liquid will stick to the solid surface , i.e will meet it if the force of adhesion A is greater than net force of cohension C . The liquid will not the solid surface if C gt A Also , molecules like Q at the surface in contact with the solid will experience a net force of cohension C_(R) . If adhesion A is greater then cohension C_(R) , the resultant force will be F . As the liquid can't support tangential force , F must be perpendicular to the surface of the liquid . So , the menisus will be concave and the angle of contact will be acute ( gt 90^(@)) . However , if adhesion is lesser than cohension , the resultant force F will be directed into the liquid and so the menisus ( which is perpendicular to F as liquid support tangential force ) will be convex and the angle of contact will be obtuse ( gt 90^(@)) A liquid particle B , which is present in the vicinity particle A can exert a force on A if the distance of B from A is

(a) H_(2)^(+)and H_(2)^(-) ions have same bond order but H_(2)^(-) ion is more stable. Explain. (b) N_(2) has a greater bond dissociation enthalpy than N_(2)^(+) ion hals more bond dissociation enthalpy than O_(2). Why ? (c ) Can we have ahomonuclear diatomic molecule with all its ground state molecular orbitals full of electrons ? (d) When a magnet is dipped in a jar of liquid oxygen, some oxygen clings to it. Assign reason :

Which of the statements about the reaction below are incorrect? 2PbO(s) + C(s) rarr 2Pb(s) + CO_(2)(g) (a) Lead is getting reduced. (b) Carbon dioxide is getting oxidised. (c) Carbon is getting oxidised. (d) Lead oxide is getting reduced.

Consider the following statements about Buckminster fullerene ( C_60 ). I. It is aromatic in nature. ll. C is s p^2 -hybridised. III. It has only six-membered rings. Choose the incorrect statement(s).

Among the statements (a)-(d) , the correct ones are : (a) Lithium has the highest hydration enthalpy among the alkali metals. (b) Lithium chloride is insoluble in pyridine. (c) Lithium cannot form ethynide upon its reaction with ethyne. (d) Both lithium and magnesium react slowly with H_(2)O