Write the resonance structures for SO3, NO2 and .
Resonance is defined as the phenomenon as a result of which a molecule can be expressed in different forms, none of which can explain all the properties of the molecules. The actual structure of the molecule is called resonance hybrid.
The resonating structures must have same position of the atoms, they must have same number of paired & unpaired electrons, they should have nearlt same energy. The resonance structures are:
(a) SO3:
(b) NO2
(c)
The mass of an electron is 9.1 × 10–31 kg. If its K.E. is 3.0 × 10–25 J, calculate its wavelength.
Calculate the amount of carbon dioxide that could be produced when
(i) 1 mole of carbon is burnt in air.
(ii) 1 mole of carbon is burnt in 16 g of dioxygen.
(iii) 2 moles of carbon are burnt in 16 g of dioxygen.
Calculate the wavelength of an electron moving with a velocity of 2.05 × 107 ms–1.
Balance the following redox reactions by ion – electron method :
(a) MnO4 – (aq) + I – (aq) → MnO2 (s) + I2(s) (in basic medium)
(b) MnO4 – (aq) + SO2 (g) → Mn2+ (aq) + HSO4– (aq) (in acidic solution)
(c) H2O2 (aq) + Fe 2+ (aq) → Fe3+ (aq) + H2O (l) (in acidic solution)
(d) Cr2O7 2– + SO2(g) → Cr3+ (aq) + SO42– (aq) (in acidic solution)
In a process, 701 J of heat is absorbed by a system and 394 J ofwork is done by the system. What is the change in internal energy for the process?
What will be the minimum pressure required to compress 500 dm3 of air at 1 bar to 200 dm3 at 30°C?
In a reaction A + B2 → AB2 Identify the limiting reagent, if any, in the following reaction mixtures.
(i) 300 atoms of A + 200 molecules of B
(ii) 2 mol A + 3 mol B
(iii) 100 atoms of A + 100 molecules of B
(iv) 5 mol A + 2.5 mol B
(v) 2.5 mol A + 5 mol B
At 0°C, the density of a certain oxide of a gas at 2 bar is same as that of dinitrogen at 5 bar. What is the molecular mass of the oxide?
Which one of the following will have largest number of atoms?
(i) 1 g Au (s)
(ii) 1 g Na (s)
(iii) 1 g Li (s)
(iv) 1 g of Cl2(g)
Density of a gas is found to be 5.46 g/dm3 at 27 °C at 2 bar pressure. What will be its density at STP?
Calculate the molarity of a solution of ethanol in water in which the mole fraction of ethanol is 0.040 (assume the density of water to be one).
Consider the reactions :
2 S2O2– 3 (aq) + I2(s) → S4 O2– 6(aq) + 2I – (aq)
S2O2– 3(aq) + 2Br2(l) + 5 H2O(l) → 2SO2–4(aq) + 4Br–(aq) + 10H+(aq)
Why does the same reductant, thiosulphate react differently with iodine and bromine ?
Saline hydrides are known to react with water violently producing fire. Can CO2, a well known fire extinguisher, be used in this case? Explain.
The ejection of the photoelectron from the silver metal in the photoelectric effect experiment can be stopped by applying the voltage of 0.35 V when the radiation 256.7 nm is used. Calculate the work function for silver metal.
What is smog? How is classical smog different from photochemical smog?
Write Lewis symbols for the following atoms and ions:
S and S2–; Al and Al3+; H and H–
The ionization constant of phenol is 1.0 × 10–10. What is the concentration of phenolate ion in 0.05 M solution of phenol? What will be its degree of ionization if the solution is also 0.01M in sodium phenolate?
Statues and monuments in India are affected by acid rain. How?
Classify the following reactions in one of the reaction type studied in this unit.
(a) CH3CH2Br + HS- → CH3CH2SH + Br-
(b) (CH3)2C = CH2 + HCl → (CH3)2ClC-CH3
(c) CH3CH2Br + HO- → CH2 = CH2 + H2O + Br-
(d) (CH3)3C - CH2OH + HBr → (CH3)2CBrCH2CH3 + H2O
Ionic product of water at 310 K is 2.7 x 10-14. What is the pH of neutral water at this temperature?
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