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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 301. |
Vapour pressure of `C CL_(4)` at `25^@C` is `143` mmHg 0.05g of a non-volatile solute (mol.wt.=`65`)is dissolved in `100ml C CL_(4)`. find the vapour pressure of the solution (density of `C CL_(4)=158g//cm^2`)A. 141.93 mmB. 94.39 mmC. 199.34 mmD. 143.99 mm |
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Answer» Correct Answer - A `(P^(@)-P_(s))/(P^(@))=(w xx M)/(m W)=143 -(0.5xx154)/(65xx158)xx143` `= 143-1.07=141.93 mm`. |
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| 302. |
The vspour preesure of two pure liquids A and B are 5 and 10 torr respectively. Calculte the total pressure of the solution (in torr) obtainrd by mixing 2 mole of A and 3 mole of B.A. 120 toorB. 36 toorC. 88 torrD. 180 toor |
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Answer» Correct Answer - C `P_(m) = P_(A)^(@)X_(A) + P_(B)^(@). X_(B)` `P_(m) = 100 xx 2/5 + 80 xx 3/5=40 + 48 = 88` torr |
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| 303. |
A mixture of ethyl alcohol and propyl alcohol has a vapour pressure of 290 mm at 300K. The vapour pressure of propyl alcohol is 200 mm. if the mole fraction of ethyl alcohol is `0.6`, its vapour pressure (in mm) at the same temperature will beA. 350B. 300C. 360D. 700 |
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Answer» Correct Answer - A Mole fraction of ethyl alcohol = 0.6 Mole fraction of methyl alcohol = 0.4 A rarr Ethyl alcohol & B rarr Methyl alcohol Then `P_(T) = P_(A)^(@) X_(A) + P_(B)^(@) X_(B)` `290 = (P_(A)^(@) xx 0.60)+(200 xx 0.40) ` ` P_(A)^(@)`= (290-80)/0.60=350 mm |
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| 304. |
If the elevation in boiling point of a solution of 10 g of solute (molecular weight = 100) in 100 g of water is `Delta T_(b)`, the ebullioscopic constant of water isA. `(Delta T_(b))/10`B. `Delta T_(b)`C. `10 Delta T_(b)`D. `100 Delta T_(b)` |
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Answer» Correct Answer - B `M_(2) = (1000 xx K_(b) xx W_(2))/(W_(1) xx Delta T_(b))` `:. K_(b) = (M_(2) xx W_(1) xx Delta T_(b))/(1000 xx W_(2))=(100 xx 100 xx Delta T_(b))/(1000 xx 10) = Delta T_(b)` |
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| 305. |
Vapour pressure of `"CCl"_(4)` at `25^(@)C` is 143 mm Hg . 0.5 g of a non-volatile solute ( molar mass = `65 mol^(-1)`) is dissolved in 100 mL of `"CCl"_(4)` (density = 1.538g `mL^(-1)` ) Vapour pressure of solution is :A. 141.93 mmB. 94.39 mmC. 199.34 mmD. 143.99 mm |
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Answer» Correct Answer - A `(P_(1)^(o)-P)/P_(1)^(o)=n_(2)/n_(1)` `(143-P)/143=(0.5//65)/(158//154)` or P=141.93 mm |
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| 306. |
Vapour pressure of `"CCl"_(4)` at `25^(@)C` is 143 mm Hg . 0.5 g of a non-volatile solute ( molar mass = `65 mol^(-1)`) is dissolved in 100 mL of `"CCl"_(4)` (density = 1.538g `mL^(-1)` ) Vapour pressure of solution is :A. 141.93 mmB. 94.39 mmC. 199.34 mmD. 143.99 mm. |
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Answer» Correct Answer - A `(P_(1)^(@)-P)/P_(1)^(@)=n_(2)/n_(1), (143-p)/143 = (0.5//65)/(158//154) :. p = 141.93` |
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| 307. |
Two solutions of a substance (non-electroyte) are mixed in the following manner `480 mL` of `1.5M` of first solution with `520 mL or 1.2M` of second solution. The molarity of final solution is:A. 2.70MB. 1.344 MC. 1.50 MD. 1.20 M |
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Answer» Correct Answer - B Total molarity `=(M_(1) V_(1)+M_(2)V_(2))/(V_(1) + V_(2))` `(1.5 xx 480 + 1.2 xx 520)/(480 + 520)=1.344 M ` |
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| 308. |
The vapour pressure of two liquid P and Q are 80 torr and 60 torr respectively. The total vapour pressure obtained by mixing `3` moles of P and 2 mole of Q would beA. 140 torrB. 20 torrC. 68 torrD. 72 torr |
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Answer» Correct Answer - D `xp=3/(3 +2) = 3/5 , xQ = 2/(3 + 2)=2/5` `:. "Total" V.P. = (xP xx p_(p)^(o)) + (xQ xx p_(Q)^(0))` `V.P. = (3/5 xx 80) + (2/5 xx 60 ) = 48 + 24 = 72 "torr"` |
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| 309. |
On mixing, heptane and octane form an ideal solution. At `373K` the vapour pressure of the two liquid components (heptane and octane) are `105 kPa` and `kPa` respectively. Vapour pressure of the solution obtained by mixing `25.0` of heptane and `35g` of octane will be (molar mass of heptane `= 100 g mol^(-1)` and of octane `= 114 g mol^(-1))`:-A. 96.2 k PaB. 144.5 kPaC. 72.0 kPaD. 36.1 kPa |
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Answer» Correct Answer - C `P_("total") = x_("hep") xx P_("hep")^(@) xx x_("oct") xx P_("oct")^(@)` `n_("hep") = 25/100=0.25, n_("oct") = 35/114=0.307` `x_("hep") = 0.25/(0.25 + 0.307)=0.45` `x_("oct")=1-0.45 = 0.55` `P_("total")=0.45 xx 105 + 0.55 xx 45 kPa` `P_("total") = 47.25 + 24.75 = 72 kPa` |
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| 310. |
800 ml of 0.1 `MH_(2) SO_(4)` is mixed with 200ml of 0.8 `MH_(2) SO_(4)` The molarity of the mixture isA. 0.32B. 0.24C. 0.12D. 0.48 |
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Answer» Correct Answer - B `M_("mix")=(M_(1) V_(1) + M_(2) V_(2))/(V_(1) + V_(2))` `((0.1 xx 0.8)+(0.2 xx 0.8))/(0.8 + 0.2)= 0.24 M ` |
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| 311. |
The vapour pressure of a pure liquid A is 70 torr at 300K. It forms an ideal solution with another liquid B. The mole fration of B in the solution is 0.2 and total pressure of solution is 84 torr at 300K. The vapour pressure of pure liquid B at `26^(@)C` isA. 14B. 56C. 140D. 70 |
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Answer» Correct Answer - C `P_(A) = X_(A) xx P_(A)^(@)=(1-0.2) xx70=56 ` torr, `P_(B)=P_("total")-P_(B)=84-56=28` torr `P_(B)=X_(A) xx P_(B)^(@)` or `p_(B)^(@)= P_(B)//X_(B)=28//0.2=140` torr |
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| 312. |
5 mL of acetone is mixed with 100mL of `H_(2)O`. The vapour pressure of water above the solution isA. equal to the vapour pressure of pure waterB. equal to the vapour pressure of the solutionC. less than the vapour prssure of pure waterD. more than tha vapour pressure of pure water |
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Answer» Correct Answer - C V.P. of any component in the solution = mole fraction of the component x V.P. of that component in the pure state and mole fraction is always lt 1. |
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| 313. |
Benzene and toluene form nearly ideal solution. At `20^(@)C` the vapour pressure of benzene is 75 torr and that of toluene is 22 torr. The partial vapour pressure of benzene at `20^(@)C` for a solution containing 78g of benzene and 46 g of toluene in torr is-A. 50B. 25C. `37.5`D. `53.5` |
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Answer» Correct Answer - A `P_(B)=p_(B)^(@)X_(B), therefore P_(B)=((78)/(78))/((78)/(78)+(46)/(92))xx75, therefore P_(B)=50` torr |
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| 314. |
Which one of the following statements is incorrect ?A. Normality of a solution depends on temperatureB. Molality of a solution depends on temperatureC. Molarity of a solution depends on temepratureD. Molality of a solution relates to mass of solvent and moles of solute |
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Answer» Correct Answer - B Molality independent on temperature. |
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| 315. |
Which of the following statements is incorrect about a solution ?A. A solution is always a homogeneous mixture.B. The solute particles in a solution have size less than 10 A.C. Brass connot be called a solution.D. An ionic compound dissolves in water if the hydration energy is greater than lattice energy. |
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Answer» Correct Answer - C Brass is a solution of solid in solid (Cu+Zn). |
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| 316. |
Usually, `CaCl_(2)` is prefferred over NaCl for cleaning snow on roads particular in very cold countries. This is becauseA. NaCl makes the road slippery but `CaCl_(2)` does notB. `CaCl_(2)` is hygroscopic but NaCl is notC. `CaCl_(2)` is less soluble in `H_(2)O` than NaClD. eutectic mixture of `CaCl_(2)/ H_(2)O` freezes at `-55^(@)C` while that of `NaCl/ H_(2)O` freezes at `-18^(@)C` |
| Answer» Correct Answer - d | |
| 317. |
If mole fraction of the solvent in a solution decreases than:A. vapour pressure of solution increasesB. boiling point decreasesC. osmotic point decreasesD. all are correct |
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Answer» Correct Answer - C Mole fraction of solvent decreases means mole fraction of solute increases. |
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| 318. |
Which one of the following ststement is incorrect?A. Greater the lowering nof vapour pressure, greater is the boiling point of the solutionB. Greater the lowering of vapour pressure, greater is the freezing point of the solution.C. At the freezing point, the solute and the solvent have same vapour pressureD. The units of molal depression constant are `K m^(-1)`. |
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Answer» Correct Answer - B Greater the lowering of V.P., greater is the depression in F.pt, i.e., lower is actual F pt. |
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| 319. |
A liquid is kept in a closed vessel. If a glass plate (negligible mass) with a small hole is kept of top the liquid surface, then the vapour pressure of the liquid in the vessel is :A. more than what would be if the glass plate were removedB. same as what would be if the glass plate were removedC. lass than what would be if the glass plate were removedD. cannot be predicted |
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Answer» Correct Answer - D Vapour pressure is characteristic property of a solvent at a temperature. |
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| 320. |
The molarity of a solution obtained by mixing 750 mL of 0.5 M HCl with 250 mL of 2 M HCl will beA. 0.975 MB. 0.875 MC. 1.00 MD. 1.75 M |
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Answer» Correct Answer - B `M_(1) V_(1) + M_(2) V_(2) = M_(3) (V_(1) + V_(2))` `0.5 xx 750 + 2 xx 250 = M_(3) (750 + 250)` or `375 + 500 = 1000 m_(3)` `M_(3) = 875/1000 = 0.875 M` |
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| 321. |
Which one of the following is an isotonic pair of solution ?A. 0.15 M NaCI and `0.1 M Na_(2)SO_(4)`B. 0.2 M urea and 0.1 M sugarC. `0.1 M BaCI_(2)` and `0.1 M NH_(4)CI`D. `0.2 M MgSO_(4)` and `0.1 M NH_(4)CI` |
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Answer» Correct Answer - A `NaCI rarr Na^(+) + CI^(-)` 0.15 NaCI contains `0.15 xx 2 = 0.3 ` M particles `NaSO_(4) rarr 2Na^(+) + SO_(4)^(2-)` `:. 0.1 M Na_(2)SO_(4)` contains `0.1 xx 3 = 0.3` M particles :. They are isotonic solutions. |
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| 322. |
A solution of sucrose (molar mass `= 342 "g mol"^(-1)`) has been prepared by dissolving 68.5g of sucrose in 1000g of water. The freezing point of the solution obtained will be : (`K_(f)` for water `= 1.86 "K kg mol"^(-1)`)A. `-0.372^(@)C`B. `-0.520^(@)C`C. `+0.372^(@)C`D. `-0.570^(@)C` |
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Answer» Correct Answer - A `Delta T_(f) = K_(f) m` Here, `m = 68.5/(342 xx 1)` `:. Delta T_(f) = 0.2000 xx 1.86 = 0.3725^(@)C` `T_(f) = 0^(@) -0.3725^(@)C= -0.3725^(@)C` |
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| 323. |
Which of the following is incorrect?A. Mass of the gas dissolved is inversely proportional to its pressureB. Mass of the gas dissolved is inversely proportional to temperatureC. A soda-water bottle contains oxygen gas dissolved under pressureD. permanent gases are less soluble than temperature gasses. |
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Answer» Correct Answer - C A soda -water bottle contains`CO_(2)` gas dissolved under pressure. |
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| 324. |
A solution of sucrose (molar mass = 342 g/mol) is prepared by dissolving 68.4 g of it per litre of solution, what is its osmotic pressure at 273 K? `(R = 0.081 L atm K^(-1) mol^(-1))`A. 3.92 atmB. 4.48 atmC. 5.92 atmD. 29.4 atm |
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Answer» Correct Answer - B `pi = CRT = W_(2)/(M_(2) xx V (dm^(3))) xx R xx T ` `= (68.4 xx 0.0821 xx 273)/(342 xx 1)=4.48 "atm"` |
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| 325. |
A`5%` solution of cane sugar (molar mass =`342`)is isotonic with `1%`of a solution of an known solute.The molar mass of unknown solute in g/mol isA. 136.2B. 171.2C. 68.4D. 34.2 |
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Answer» Correct Answer - C Isotonic solutions have equal molar concentrations. Hence, `(5//342)/100 xx 1000 = (1//M)/100 xx 1000` or `5/342 =1/M` or `M=68.4` |
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| 326. |
The use of common salts, e.g., `NaCl` or `CaCl_(2)` anhydrous, is made to clear snow on the rods. This causes:A. a lowering in f. pt.of waterB. a lowering in m. pt. of iceC. ice melts at the temperature of atmosphere present at that timeD. all |
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Answer» Correct Answer - A Addition of salt lowers the freezing point of water and thus show melts. |
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| 327. |
Which of the following statement is correct?A. Lowering of vapour pressure takes place only in ideal solutions.B. Lowering of vapour pressure does not depend upon the solvent at a given concentration of the solute.C. Lowering of vapour pressure depends upon the nature of the solute.D. Relative lowering of vapour pressure does not depend upon the solvent at a given concentration of solute. |
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Answer» Correct Answer - D Relative lowering of V.P.= Mole fraction (conc.)of solute only. |
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| 328. |
Which one of the following is not a colligative property?A. Refractive indexB. Osmotic pressureC. Lowering of vapour pressureD. Elevation in boiling point |
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Answer» Correct Answer - A Colligative properties are osmotic pressure `Delta P,` ` Delta T_(b)` and `Delta T_(f)` |
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| 329. |
The boiling point of solution containing 68.4 g of sucrose `("molar mass" = 342 g mol^(-1))` in 100 g of water is `(K_(b) "for water" = 0.512 K. kg mol^(-1))`A. `100.02^(@)C`B. `98.98^(@)C`C. `101.02^(@)C`D. `100.512^(@)C` |
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Answer» Correct Answer - C `Delta T_(b) = K_(b) xx m = K_(b) xx W_(2)/(M_(2) xx W_(1) (kg))` `=0.512 xx 68.4/(342 xx 0.1) = 1.024 ^(@) C ` ` :. T_(b) = T_(b)^(o) + Delta T_(b) =100 ^(@) C + 1.024^(@)C=101.024^(@)C` |
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| 330. |
Which is not a colligative property?A. A tmospheric pressureB. Lowering of vapour pressureC. osmotic pressureD. Elevation of freezing point. |
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Answer» Correct Answer - A The atmospheric pressure not is a colligative property. |
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| 331. |
The colligative properties of a solution depend onA. number of solute particles present in itB. chemical nature of the solute particles present in itC. nature of the solvent usedD. none |
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Answer» Correct Answer - A `Cp prop n.` |
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| 332. |
Which is not a colligative property?A. Refractive indexB. Lowering of vapour pressureC. Depression of freezing ppointD. Elevation of boilling point |
| Answer» Correct Answer - A | |
| 333. |
Which is not a colligative property?A. pH of a buffer solutionB. Boiling point elevationC. Freezing point depressionD. Vapour pressure |
| Answer» Correct Answer - A | |
| 334. |
Which of the following is not a colligative property ?A. Optical activityB. Elevation in boiling pointC. Osmotic pressureD. Lowering of vapour pressure |
| Answer» Correct Answer - A | |
| 335. |
Which of the following colligative property can provide molar mass of proteins (or polymers or colloids) with greatest precision?A. Relative lowering of vapour pressureB. Elevation of boiling pointC. Depression in freezing pointD. Osmotic pressure. |
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Answer» Correct Answer - D Except osmotic pressure, value of any other colligative property for a polymer is too small to be measured. |
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| 336. |
An example of colligative property isA. Freezing pointB. Boiling pointC. Vapour pressureD. Osmotic point |
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Answer» Correct Answer - D `pi prop n.` |
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| 337. |
Which of the following is a colligative property ?A. Osmotic pressureB. Boiling pointC. Vapour pressureD. Freezing point |
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Answer» Correct Answer - A Osmotic pressure is colligative property. |
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| 338. |
A solution of urea (mol. mass 60g `mol^(-1)`) boils at `100.18^(@)C` at the atmospheric pressure. If `K_(f)` and `K_(b)` for water are 1.86 and `0.512 kg mol^(-1)` respectively the above solution will freeze atA. `-6.54^(@)C`B. `6.54^(@)C`C. `0.654^(@)C`D. `-0.654^(@)C` |
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Answer» Correct Answer - D `Delta T_(b)=0.18 , Delta T_(b)=m K_(b)` `(0.18)/(Delta T_(f))=(mK_(b))/(m K_(f)) , (0.18xx1.86)/(0.512)=Delta T_(f) , Delta T_(f)=0.653` `T^(+)-T_(s)=0.653 , T_(s)=0-0.653^(@)C , T_(s)=-0.653^(@)C` |
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| 339. |
Assertion :- If 100 cc of 0.1N HCl is mixed with 100 cc of 0.2 N HCl, the normality of the final solution will be 0.30. Reason :- Normalities of similar solutions like HCl can be added.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If asserrion is false but reason is true. |
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Answer» Correct Answer - D If 100 cc of 0.1 N HCl is mixed with 100 cc of 0.2 N HCl the normality of the final solution will be 0.15. `N_(1)V_(1)+N_(2)V_(2)=N_(3)V_(3) i.e., 0.1xx100+0.2xx100` `=N_(3)xx200` or `N_(3)=(0.3xx100)/(200)=0.15` |
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| 340. |
Dissolving 120g of urea (mol.wt.60) in 1000g of water gave a solution of density 1.15 g/mL. The molarity of the solution isA. 1.78 MB. 2.00 MC. 2.05 MD. 2.22 M |
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Answer» Correct Answer - C Mole `=(120)/(60)=2` mass of solution = 1120 g `V=(1120)/(1.15xx100)=(112)/(115)L` `M=(2xx115)/(112)=2.05` mol/litre |
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| 341. |
Assertion :- One molal aqueous solution of urea contains 60g of urea in 1kg (1000 g) water. Reason :- Solution containing one mole of solute in 1000g solvent is called as one molal solution.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If the assertion and reason both are false. |
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Answer» Correct Answer - A Molecular weight of urea `(NH_(2)CONH_(2))` `=14+2+12+16+14+2=60` Number of moles `=("Weight")/("molecular weight")=(60)/(60)=1` |
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| 342. |
Assertion :- One molal aqueous solution of glucose contains 180g of glucose in 1 kg water. Reason :- Solution containing one mole of solute in 1000g of solvent is called one molal solution.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If the assertion and reason both are false. |
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Answer» Correct Answer - A Molality `=("Number of moles of sollute")/("weight of solvent (in kg)")` If number of moles of solute = 1 Weight of solvent = 1 kg then, molality = 1, i.e., one molala For glucose `(C_(6)H_(12)O_(6))` , molecular weight = 180 number of moles `=(180)/(180)=1`, weight of water = 1 kg Hence, molality of the solution is one. |
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| 343. |
The molal b.pt constant for water is `0.513^(@)C "kg mol"^(-1)`. When 0.1 mole of sugar is dissolved in 200g of water, the solution boils under a pressure of 1 atm at :A. `100.513^(@)C`B. `100.0513^(@) C`C. `100.256^(@)C`D. `101.025^(@)C` |
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Answer» `Delta T_(b) = K_(b) xx m 0.51 xx (0.1/200 xx 1000)=0.2565^(@)C` `T_(b) = T^(@) + Delta T_(b) = 100 + 0.2565^(@) C=100.2565^(@) C` |
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| 344. |
The total number of gm-molecules of `SO_(2)Cl_(2)` in 13.5 g of sulphuryl chloride isA. `0.1`B. `0.2`C. `0.3`D. `0.4` |
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Answer» Correct Answer - A Gram molecule of `SO_(2)Cl_(2)=135` `n=(w)/(m)=(13.5)/(135)=0.1`. |
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| 345. |
Which aqueous solution has minimum freezing point?A. 0.01 m NaCIB. 0.005 m `C_(2) H_(5) OH`C. `0.005 m MgI_(2)`D. `0.005 m MgS)_(4)`. |
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Answer» Correct Answer - A `0.01 m NaCI equiv 0.02 m Na ^(+)` and `CI_(-)` ions which is maximum. Hence, depression in F. pt is max. or actual F. pt is minimum. |
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| 346. |
If `pi_(1)` is the osmotic pressure of solution containing 6 g. of acetic acid per `dm^(3)` and `pi_(2)` is that of a solution containing 5.85 g. of NaCl per `dm^(3)` at the same temperature thenA. `pi_(1) lt pi_(2)`B. `pi_(1) gt pi_(2)`C. `pi_(1) = pi_(2)`D. `2pi2pi_(1)=pi_(2)` |
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Answer» Correct Answer - A Both the solutions are one molar but NaCl being an electrolyte will have more, O.P. then acetic acid which is non electrolyte. |
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| 347. |
The molal depression constant depends uponA. nature of the solute]B. nature of the solventC. heat of solution of the solute in the solventD. vapour pressure of the solution. |
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Answer» Correct Answer - B Molal depression constant depends only on the nature of the solvent. |
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| 348. |
Acetic acid on dissolution in benzene will showA. half of its normal molecular massB. its normal molecular massC. two time of its normal molecular massD. none |
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Answer» Correct Answer - C A cetic acid dimerises in benzene. |
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| 349. |
Dissolution of a solute is an exothermic process ifA. Hydration energy gt Lattice energyB. Hydration energy lt Lattice energyC. Hydration energy = Lattice energyD. None |
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Answer» Correct Answer - A `Delta H_("solution")= Delta H_("hydration") + Delta H_("lattice energy")` `Delta H_(h) = -ve` `Delta H_(1) = + ve ` |
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| 350. |
The plant cell shrink when placed in aA. waterB. a hypotonic solutionC. a hypertonic solutionD. an isotonic solution |
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Answer» Correct Answer - C When plant cell placed in hypertonic solution,the water flows from plant cell to the solution due to osmosis. |
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