Practice Questions

Q48.Ferrous sulphate heptahydrate is used to fortify foods with iron. The amount (in grams) of the salt required to achieve 10ppm of iron in 100kg of wheat is ____________. Atomic weight: Fe = 55.85; S = 32.00; O = 16.00

Q48.The rate of a reaction decreased by 3. 555 times when the temperature was changed from 40 °C to 30 °C . the activation energy (in kJ mol−1 ) of the reaction is ________ .

Q49.The sum of the total number of bonds between chromium and oxygen atoms in chromate and dichromate ions is ______________. JEE Main 2020 (09 Jan Shift 2) JEE Main Previous Year Paper

Q49.An element with molar mass 2 .7 ×10−2 kg mol−1 forms a cubic unit cell with edge length 405 pm. If its density is 2. 7 × 103 kg m−3 , the radius of the element is approximately … … … . ×10−12m (to the nearest integer)

Q49.The mass of gas adsorbed, x, per unit mass of adsorbate, m, was measured at various pressures, p. A graph between log mx and log p gives a straight line with slope equal to 2 and the intercept equal to 0. 4771 . The value of x at a pressure of 4 atm is : m (Given log 3 = 0. 4771 )

Q49.The number of molecules with energy greater than the threshold energy for a reaction increases five fold by a rise of temperature from 27oC to 42oC. Its energy of activation in J/ mol is _________ (Take ln 5 = 1. 6094; R = 8. 314 J mol−1 )

Q49.What would be the electrode potential for the given half-cell reaction at pH = 5? _________. ⊕ 2H2O →O2 + 4 H + 4e−; E0red = 1.23V (R = 8.314Jmol−1K−1; Temp = 298K; oxygen under s tan dard . atm. pressureof1bar)

Q49.For Freundlich adsorption isotherm, a plot of log (x/m) (y −axis) and log p(x −axis) gives a straight line, the intercept and slope fo rthe line is 0. 4771 and 2 , respectively. The mass of gas, adsorbed per gram of adsorbent if the initial pressure is 0. 04 atm is _____ ×10−4g .

Q49.If 75% of a first order reaction was completed in 90 minutes, 60% of the same reaction would be completed in approximately (in minutes) _____ (Take: log 2 = 0.30 ; log 2.5 = 0.40)

Q49.Considering that Δ0 > P , the magnetic moment (in BM) of [Ru (H2O)6]2+ would be

Q49.The flocculation value of HCl for arsenic sulphide sol is 30 mmolL−1 . If H2SO4 is used for the flocculation of arsenic sulphide, the amount, in grams, of H2SO4 in 250ml required for the above purpose is ________ (molecular mass of H2SO4 = 98 g/mol

Q49.For an electrochemical cell Sn(s) Sn2 + (aq, 1M) Pb2+(aq, 1M) Pb(s) the ratio [Sn2+] when this cell [Pb2+] attains equilibrium is _______ (Given: E0 = −0 .14 V, E0 = −0 .13 V, 2.303RTF = 0 .06 ) Sn2+ Sn Pb2+ Pb

Q49.Potassium chlorate is prepared by the electrolysis of KCl in basic solution 6 OH−+ Cl−→ClO−3 + 3H2O + 6e− . If only 60% of the current is utilized in the reaction, the time (rounded to the nearest hour) required to produce 10g of KClO3 using a current of 2A is … … . . (Given : F = 96, 500Cmol; molar mass of KClO3 = 122 g mol−1 )

Q50.Consider the following reactions A (i)CH3MBr B 573KCu 2 −methyl −2 −butene . The mass percentage of (ii)H3O+ carbon in A is _____________.

Q50.A solution of phenol in chloroform when treated with aqueous NaOH gives compound Pas a major product. The mass percentage of carbon in P is ______ .

Q50.The number of chiral carbons in chloramphenicol is ____________.

Q50.The number of chiral carbon(s) present in peptide, lle-Arg-Pro, is ................

Q50.The number of chiral carbons present in sucrose is ……….

Q50.The number of Cl = O bonds in perchloric acid is, ′′… … … . . .′′ β3 8 α3 8 is :

Q50.The number of chiral centres in penicillin is _________.

Q50. The number of groups present in a tripeptide Asp – Glu – Lys is ____

Q50.The number of chiral centres present in [B] is _____

Q50.The number of sp2 hybridised carbons present in “Aspartame” is

Q50.The oxidation states of iron atoms in compounds (A), (B) and (C), respectively, are x, y and z. Then sum of x, y and z is ........... Na4[Fe (CN)5(NOS)] Na4[FeO4] [Fe2 (CO)9] (A) (B) (C)

Q50.For the disproportionation reaction 2 Cu+(aq) ⇌Cu(s) + Cu2+(aq) at 298K,ln K (where K is the equilibrium constant) is _______ ×10−1 Given : (E°Cu2+ / Cu+= 0. 16V E°Cu+ / Cu= 0. 52V RTF = 0. 025)