This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
A weak acid HX has the dissociation constant 1xx10^(-5)M. It forms a salt NaX on reaction with alkali. The degree of hydrolysis of 0.1 M solution of NaX is |
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Answer» `0.0001%` `:. (10^(-14))/(10^(-5))=0.1xxh^(2) or h^(2) = 10^(-8) or h = 10^(-4)` % hydrolysis `= 10^(-4) xx 100 = 10^(-2) = 0.01` |
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| 2. |
A weak acid HX has K_(a) =1 xx 10^(-5)M. If forms a salt NaX onreaction with alkali. The perentage degree of dissociation of 0.1 M solution of NaX is |
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Answer» 1.0E-5 For the salt `K_(h) =(K_(w))/(K_(a)) =Calpha^(2)` `:. (10^(-4))/(10^(-5)) =0.1 alpha^(2)` `" or """alpha^(2) =(10^(-14))/(10^(-6)) =10^(-8)` `alpha =(10^(-8))^(1//2) =10^(-4)` `% " degree of DISSOCIATION "underset(=10^(-2) =0.01%)(=10^(-4) XX 100)` |
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| 3. |
A weak acid HX, after mixing with 12 mL of decimolar potash has a pH 5. At the end point of neutralisation 26.6 mL of potash is consumed. What is the dissociation constant of HX ? |
| Answer» SOLUTION :`8.2 XX 10^(-6)` | |
| 4. |
A weak acid HX has the dissociation constant 1xx 10 ^(-5)M.It forms a salt NaX on reactions with alkali. The percentage hydrolysis of 0.1 M solution of NaX is : |
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Answer» `0.0001 %` ` % h= 0.01 %` |
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| 5. |
A water sample has ppm level concentration of the following metals: Fe = 0.2 , Mn = 5.0 , Cu = 3.0, Zn = 5.0. The metal that makes the water sample unsuitable for drinking is.... |
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Answer» Cu |
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| 6. |
A wave has a frequency of 3 xx 10^(15) sec^(-1). The energy of that photon is |
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Answer» `1.6xx10^(-12)` erg |
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| 7. |
A water sample is said to contain permanent hardness if water contains |
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Answer» SULPHATES and chlorides of CALCIUM and magnesium |
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| 8. |
A water sample has ppm level concentration of following anions F^(-)=10 , SO_4^(2-)=100 , NO_3^(-)=50 The anion/anions that make/makes the water sample unsuitable for drinking is/are |
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Answer» only `F^-` |
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| 9. |
A water sample has ppm level concentration of following anions. F^(-) = 10, SO_(4)^(2-) = 100, NO_(3)^(-) = 50 The anion/anions that make/makes the water sample unsuitable for drinking is/are…….. |
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Answer» only `NO_(3)^(-)` `NO_(3)^(-)` up to 50 ppm `SO_(4)^(2-)` up to 500ppm |
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| 10. |
A water sample has ppm level concentration of following anions F^(-)=10,SO_(4)^(2-)=100,NO_(3)^(-)=50 The anion/anions that make/makes the water sample unsuitable for drinking is/are: |
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Answer» only `F^(-)` |
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| 11. |
(A) : Water is a liquid whereas sulphurdi oxide is a gas at room temp (R) : Molecular mass of SO_2 is more than that of H_2 O |
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Answer» Both (A) and (R) are true and (R) is the CORRECT EXPLANATION of (A) |
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| 12. |
(a) W hat do ou mean by catensation? (b) C Cl_(4) cannot be hydrolysed, but SiCl_(4) can be easily hydrolysed, Why? |
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Answer» Solution : (a) F or answer, CONSULT section 11.6. (B)For answer, Consult section 11.7. |
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| 13. |
(A): Volume to temperature ratio is constant for a fixed amount of gas at constant pressure. (R) : At constant pressure the volume of a given mass of a gas increases or decreases by 1/273 times of its volume at 0^@C, for every 1^@C change in temp. |
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Answer» Both A and R are CORRECT and R is the correct EXPLANATION of A. |
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| 14. |
A vey high cosmic abundance of Fe is due to |
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Answer» its ferro-magnetic nature |
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| 15. |
A vessel with small opening contained equal volumes of oxygen and an unknown gas. Oxygen effused through the opening 1.8 times faster than the unknown gas. If the atomic mass of oxygen is 16, calculate the molecular mass of the unknown gas. |
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Answer» Solution :Graham.s LAW of diffusion is also applicable to the phenomenon of EFFUSION. According to this law, `r_1/r_2 = sqrt(M_2/M_1)` SINCE, oxygen EFFUSES 1.8 times FASTER than the unknown gas, we have `r_1/r_2 = 1.8` Suppose the molecular mass of the unknown gas is `M_2`. Hence, `1.8 = sqrt(M_2/32)( :. "Molecular mass of " O_2 = 32)` or`M_2 = 103.68` |
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| 16. |
A vessel of 120 mL capacity contains a certain mass of a gas at 20^(@)C and 750 mm pressure. Thegas was transferred to a vessel whose volume is 180 mL. Calculate the pressure of the gas at 20^(@)C. |
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Answer» Solution :Since a gas completely fills the vessel in which it is contained, thesefore, we have : `V_(1)=120 mL,V_(2)=180 mL`,`P_(1)=750 mm, P_(2)=?mm` Since the temperature REMAINS CONSTANT, therefore, by applying Boyle's Law, `P_(1)V_(1)=P_(2)V_(2)` |
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| 17. |
A vessel of 25 litre capacity contains 10 moles of steam under pressure of 50.3 atm. Calculate the temperature of steam using van der Waals equation (if for water a=5.46 bar L^2 mol^(-2) and b=0.031 L mol^(-1)) |
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Answer» 1539.5K |
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| 18. |
A vessel of 120 mL capacity contains a certain amount of gas at temperature 35^(@)C and 1.2 bar pressure. The gas is transferred to another vessel of volume 180 mL at temperature 35^(@)C, What would be its pressure ? |
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Answer» Solution :When FIXED mass of any gas is POURED to one container to another container then its pressure, volume and temperature is as under. Container - 1st : Initial volume `(V_(1))=120` ML Initial pressure `(p_(1))=1.2` bar Temperature `(T) = 35^(@)C` Container - 2nd : Final volume `(V_(2))=180` mL Temperature (T) `= 35^(@)C` Final pressure `(p_(2))=(?)` Temperature is constant at `35^(@)C` and mass of gas is constant so according to Boyle.s LAW. `p_(1)V_(1)=p_(2)V_(2)` `therefore p_(2)=(p_(1)V_(1))/(V_(2))=(("1.2 bar")xx(120 mL))/(180 mL)=0.8` bar Pressure of container - 2nd would be 0.8 bar. |
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| 19. |
A vessel of 120 mL capacity contains a certain amount of gas at 35^(@)C and 1.2 bar pressure. The gas is transferred to another vessel of volume 180 mL at 35^(@)C. What would be its pressure ? |
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Answer» <P> Solution :`V_(1)=120 ML,""P_(1)=1.2 bar, "" T_(1)=35^(@)C``V_(2)=180 mL, ""P_(2)=?, ""T_(2)=35^(@)C` As temperature remains CONSTANT,APPLYING Boyle's law, `P_(1)V_(1)=P_(2)V_(2)` `(1.2"bar")(120 mL)=P_(2)(180 mL) or P_(2)=0.8 "bar"` |
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| 20. |
A vessel of 120 mL capacity contains a certain amount of gas at 35^(@)C and 1.2 bar pressure. The gas 1p transferred to another vessel of volume 180 mL at 35^(@) C. What would be its pressure ? |
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Answer» Solution :`P_(1)=1*2` bar `P_(2) =?, v_(1)=120 ML, v_(2)=180 mL` TEMPERATURE contant. According contant. According to Boyle.s law `P_(1)V_(1)=P_(2)V_(2) `or `P_(2) =(P_(1)V_(1))/(V_(2))=(1*2 "bar" xx12 mL)/(180mL)=0*8 "bar"`. |
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| 21. |
A vessel of 120 mL capacity contains a certain amount of gas at 35 ^(@)C and 1.2 bar pressure. The gas is transferred to another vessel of volume 180 mL at 35 ^(@)C. What would be its pressure? |
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Answer» SOLUTION :Since temperature REMAINS constant, we have according to Boyle.s LAW, `P_1 V_1 = P_2 V_2` or `1.2 xx 120 = P_2 xx 180` or `P_2 =(1.2xx120)/180 = 0.8`bar |
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| 22. |
A vessel of 10L was filled with 6 mole of Sb_(2)S_(3) and 6 mole of H_(2) to attain the equilibrium at 440^(@)C as: Sb_(2)S_(3)(s)+3H_(2)(g)hArr2Sb(s)+3H_(2)S(g) After equilibrium the H_(2)S formed was analysed by dissolving it in water and treating with excess of Pb^(2+) to give 708 g "of" PbS as precipitate. What is value of K_(c) of the reaction at 440^(@)C?(At. weight of Pb=206). |
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Answer» `0.08` `Sb_(2)S_(3)(s)+3H_(2)(g)hArr2Sb(s)+3H_(2)S(g)` `{:("Initial",6,6,0,0),("at EQ.",5,3,2,3):}` `K_(c)=((3//10)^(3)xx(2//10)^(2))/((5//10)xx(3//10)^(3))=(4)/(50)=0.08` |
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| 23. |
A vessel is filled with a mixture of oxygen and nitrogen . At what ratio of partial pressures will the mass of the gases be indentical ? |
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Answer» Solution :`PV=nRT=(W)/(M)RT` `P_(O_(2))V=(w_(O_(2)))/(32)xxRT` `P_(N_(2))V=(w_(N_(2)))/(28)xxRT` `:. "" (P_(O_(2)))/(P_(N_(2)))=(w_(O_(2)))/(32)xx(28)/(w_(N_(2)))=(28)/(32)""(because w_(O_(2))=w_(N_(2)))` `=(7)/(8)=7:8` |
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| 24. |
A vessel of irregular shape has a volume 'V'. It is first evacuated and coupled with a vessel of 4L capacity at 35^@C and 10 atm pressure. If the final pressure in both the vessels is 3atm, calculate the volume V. |
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Answer» Solution :UNKNOWN vesselKnown vessel `V_(1) = VL ""V_(2) = 4L` `P_(1) = 0 "atm" P_(2) = 10` atm The average pressure (P) of the mixture of the GASES from two vessels ` = P = (P_(1)V_(1)+ P_(2)V_(2))/(V_(1) + V_(2))` ` 3 = (0 XX V + 10 xx 4)/(V + 4) = (40)/(V + 4)` Solving, V = 9.3 L The volume of the given vessel of irregular shape is 9.3 L |
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| 25. |
A vessel has N_2 gas saturated with water vapour at a total pressure of 1 atm. The partial pressure of water vapour is 0.3 atm. The contents of this vessel are completely transferred to another vessel having one third of the capacity of the original volume, at the same temperature. The total pressure of this system in the new vessel is |
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Answer» 3.0 ATM `1 = P_1 + 0.3 implies P_1 = 0.7 atm` on making volume = `(V_1)/3`, PRESSURE `P_2 = 3P_1 = 3 xx 0.7 = 2.1 atm`. `P_(H_2O)` does not change `:.` NEW `P_(N_2) = 2.1 + 0.3 = 2.4 atm.` |
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| 26. |
A vessel contains N_(2)O_(4) & NO_(2) in 2:3 molar ratio at 10 atm under equilibrium. Now, K_(P) for N_(2)O_(4) harr 2NO_(2) is |
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Answer» 9 ATM `K_(P)=(P_(NO_(2))^(2))/(P_(N_(2)O_(4)))=(((3)/(5) xx 10)^(2))/((2)/(5) xx 10)=9` atm |
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| 27. |
A vessel contains N_(2) O_(4) at certain temperature & 2 atm . If the degree of dissociation of N_(2) O_(4) at equilibrium is 0.2 , final pressure of system (in atm) ? |
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Answer» `1.2` |
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| 28. |
A vessel contains methane and oxygen in the mass ratio 2:1. The fraction of the partial pressure of oxygen in the total pressure is |
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Answer» `1//3` |
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| 29. |
A vessel contains helium and methane in 4:1 molar ratio at 20 bar pressure. Due to leakage, the mixture of gases starts effusion. Find the composition of the mixture in the initial stage. (Hint: According to Graham's law of effusion, the rate of effusion of a gas in the mixture r prop Partial pressure sqrt((1)/( "molecular mass")) |
| Answer» SOLUTION :`He:CH_4 =8:1` | |
| 30. |
A vessel contains He and H_(2) in the molar ratio 1 : 5. The ratio of mean transitional kinetic energies, at the same tempreatures is |
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Answer» Solution :(d) `KE=(3)/(2)PV=(3)/(2)nRT` `((KE)He)/((KE)H_(2))=((3)/(2)RT)/((3)/(2)RT)((1)/(5))=1 : 5` |
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| 31. |
A vessel contains helium and methane in 4:1 mole ratio at 20 bar pressure. Find the ratio of initial rates of effusion through a small aperture. |
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Answer» <P> Solution :Ratio of moles of He and `CH_(4)` = 4 : 1Ratio of partialpressure of He and `Ch_(4) = 4 :1` Total pressure of the mixture = 20 bar Partial pressure of He ` = 20 xx (4)/(5) = 16` bar partial pressure of `CH_(4) = 20 xx (1)/(5) =4 ` bar Ratio of intial RATES of effusion is ` (r_(1))/(r_(2)) = (P_(1))/(P_(2)) sqrt((M_(2))/(M_(1))) = (16)/(4) sqrt((16)/(4)) = (4)/(1) sqrt((4)/(1))` The ratio of INITIAL rates of effusion of gases, helium and methane ` =4 sqrt(4) : 1 = 8 : 1` |
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| 32. |
A vessel contains equal weights of He and CH_(4)gases at 20 bar pressure. Due to the leakage, the gases in the vessel started effusing out. What is the volume ratio of He and CH_(4)gases coming out initally |
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Answer» <P> SOLUTION :`n_(He) = x/4 = n_1 , n_(CH_4) = x/16 = n_2 , (n_1)/(n_2) = 4/1`.`(gamma_(He))/(gamma_(CH_4)) = (P_(He))/(P_(CH_4)) SQRT(16/4) = 4/1 sqrt(16/4) = 8:1`. |
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| 33. |
A vessel contains equal volumes of SO_2 and CH_4Through a small hole, the gases effused into vacuum. After 200sec, the total volume is reduced to half. What is the ratio of SO_2and CH_4remaining in the vessel? |
| Answer» ANSWER :B | |
| 34. |
A vessel contains equal number of moles of helium and methane. Through a small orifice the half of gas effused out. The ratio of the number of mole of helium and methane remaining in the vessel is |
| Answer» ANSWER :B | |
| 35. |
A vessel contains equal masses of helium and oxygen at 35^@C. What is the ratio of kinetic energies of the components? |
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Answer» |
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| 36. |
A vessel contains a mixture of equal weights of oxygen and SO_2 at a pressure of 600mm of Hg. The partial pressure of oxygen in mm is |
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Answer» 200 |
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| 37. |
A vessel contains a mixture of equal weights of methane and sulphur dioxide al pressure of 600 mm. Find the partial pressures of each of these gases in the mixture. |
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Answer» <P> SOLUTION :`p_(CH_4) = 480mm ,P_(SO_2) = 120 MM` |
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| 38. |
A vessel contains a mixture of equal masses of helium and oxygen at a pressure of 600 torr. Calculate the partial pressures of components in the mixture. |
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Answer» Solution :Let the mass of each component gas is x. Total number of moles in the mixture = `(XG " of " He)/(4G " of " mol^(-1)) + (xg " of " O_2)/(32 g " of " mol^(-1)) = (9x)/(32 g mol^(-1))` Partial pressure = pressure of the mixture x mole FRACTION Partial pressure of He `= 600 xx (x//4)/(9x//32) = 600 xx 8/9` `= 5333.33"TORR"` Partial pressure of `O_2 = 600 xx (x//32)/(9x//32)` `= 600 xx 1/9 = 66.67` torr (or) Partial pressure of `O_2 = 600 - 533.37 ` = 66.67 torr |
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| 39. |
A vessel contains a mixture of different types of gases. Which of the following satements is correct? |
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Answer» On the average, the heavier molecules have higher molecules have higher speed |
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| 40. |
A vessel contains 1.6 g of dioxygen at STP (273.15 K, 1 atm pressure). The gas is now transferred to another vessel at constant temperature, where pressure becomes half of the original pressure. Calculate (A) volume of the new vessel. (B) number of molecules of dioxygen. |
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Answer» Solution :(A) `p_(1)=1` atm, `p_(2)=1/2 = 0.5` atm, `T_(1)=273.15, V_(2)=(?)` 32g of dioxygen occupies `=22.4 L` volume at STP `:.1.6g` dioxygen will occupy `=(22.4Lxx1.6g)/(32g)` `=1.12L` `V_(1)=1.12L` From Boyle.s law `p_(1)V_(1)=p_(2)V_(2)` `V_(2)=(p_(1)V_(1))/(p_(2))= (1 "atm"xx1.12L)/(0.5 "atm")=2.24L` Number of moles of dioxygen `=("MASS of dioxygen")/("Molar mass of dioxygen")` `n_(O_(2))=(1.6)/(32)=0.05` mol 1 mol of dioxygen contains `= 6.022xx10^(23)` molecules `:.` 0.5 mol of dioxygen CONTAIN `= 0.05xx6.022xx10^(23)` molecule `=3.011xx10^(22)` molecules |
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| 41. |
A vessel contains 100 litres of liquid X. Heat is suppplied to the liquid in such a fashion that, Heat given = change in ethalpy. The volume of the liquid is incresed by 2 litres. If the external pressure is one atm, and 202.6joules of heat were supplied then, [U= total internal energy] : |
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Answer» `DeltaU=0,DeltaH=0` |
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| 42. |
A vessel contains 100 litres of a liquid x. Heat is suppllied to the liquid in such a fashion that, Heat given = change in enthalpy. The volume of the liquid increases by 2 lites. If the external pressure is one atm and 202.6 Joules of heat were supplied then, |
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Answer» `Delta U = 0, Delta H = 0` from first law of T. D `Delta U = Q + W` `Delta U = 202.6 + (-P Delta V)` `=202.6 + (-1(2) xx 101.3J) = 0` |
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| 43. |
A vessel contains 1 mole PCI_5 (g) at 4 atm and 0.5 mole PCI_3 formed at equilibrium. Now, equilibrium pressure of mixture is (assume ideal behavior) |
Answer» Solution : given X = 0.5 total moles of equilibrium = 1+ x =1.5 moles `alpha` pressure `1 to 4`atm `1.5 to ? implies` pressure = 6atm |
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| 44. |
A vessel contains 0.25 moles of Helium and0.15 moles of neon at 298K and 2.4 atmosphere pressure. Calculate the partial pressure of each gas in the mixture. |
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Answer» Solution :TOTAL PRESSURE .P.=2.4atm No. of moles of He=0.25 No. of moles of Ne=0.15 Total moles of n=0.25+0.15=0.4 Partial pressure = Total pressure X Mole-fraction `P_(He) = (n_(He))/(n) xx P = (0,.25)/(0.4) xx 2.4 = 1.5 atm` `P_(N e) = (n_(N e))/(n) xx P = (0.15)/(0.4) xx 2.4 = 0.9 atm`. |
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| 45. |
A vesselat 1000 K containsCO_(2) with a pressure of 0.5 atm . Some of the CO_(2) is converted intoCO on the addition of graphite . If the total pressure at equilibrium is 0*8 atm , the value of K is |
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Answer» 3 atm `:. (0.5 -p) +2 p = 0.8" atm "or p=0.3 " atm "` `K=(p^(2) CO)/p_(CO_(2)) = (0.6)^(2)/((0.5 -0.3)) = (0.6 xx0.6)/0.2 = 1.8 " atm", ` |
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| 46. |
A vessel at 1000 K contains CO_(2) with a pressure of 0.5 atm. Some of CO_(2) is converted into CO on addtion of graphite. The value of K' at equilibrium when total pressure is 0.8 atm will be |
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Answer» 0.18 atm at EQM 0.5-P`""2P` P=0.3 `K=((0.6)^(2))/((0.2))=1.8`atm |
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| 47. |
A vessel at 1000 K contains CO_(2) at 0.4 atm . If certain amount of CO_(2) is converted into CO by the addition of graphite , the following equilibrium is established CO_(2) + C hArr 2CO , at a pressure of 0.6 atm, then equilibrium constant is |
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Answer» 0.2 ATM |
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| 48. |
A vessel at 1000 K contains carbon dioxide with a pressure of 0.5 atm. Some of the carbon dioxide is converted to carbon monoxide on addition of graphite. Calculate the value of K it the total pressure at equilibrium is 0*8 atm. |
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Answer» Solution :`CO_(2) (G) + C (s) hArr 2 CO (g)` Suppose decreasein pressure of `CO_(2)` after reaction = p atm Then increase in pressure due to CO= 2 p Pressure of `CO_(2)` at equilibrium `=(0.5 - p)` atm `:." Final TOTAL pressure " (0.5- p) + 2p = 0*5 + p = 0.8 " atm"`(Given) `:. p= 0*3 " atm.Hence we have "` `p_(CO_2) = 0*5 - 0*3 = 0*2 " atm "` `and ""p_(CO) = 2 xx 0*3 = 0*6 " atm" ` `:. K = (P_(cO)^(2))/P_(CO_(2)) = (0.6)^(2)/(0*2) = 1*8` |
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| 49. |
A vessel (A) contains I mole each of N_(2) & O_(2) and another vesser (B) contains 2 mole each of N_(2)& O_(2) . 3oth vessels are heated to same temperature till equilibrium is established in-both cases. Then, correct statement is |
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Answer» `K_c` for `N_2+O_2 harr 2NO` in A & B are in the ratio 1:2 |
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| 50. |
A very small amoutn of radioactive isotope of Pb^(213) was mixed with a non-radioactive lead salt containg 0.01g of Pb (atomic mss 207). The whole lead was brought into solution and lead chromate was prcipitated by addition of a soluabolr chromate. Evaporation of 10cm^(3) fo the supernatentliquid gave a residue having a radioactivity (1)/(24000) of that of the original quanity if Pb^(213) caculate the solubility of lead chromate in mol dm^(-3). |
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Answer» |
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