Chemistry

Solutions and Vapour Pressure

62 Questions

Solutions and vapour pressure questions explore boiling points, colligative properties, and osmotic pressure. These concepts are regularly tested in competitive chemistry exams. Solving these requires a solid grasp of solute and solvent interactions.

colligative propertiesvapour pressureboiling and melting pointsosmotic pressure

Solutions and Vapour Pressure Questions

Multiple choice

What are the melting and boiling points of liquid HCl?

  1. Boiling point: - 83�C and melting point: -113�C

  2. Boiling point: 93�C and melting point: 86�C

  3. Boiling point: 82�C and melting point: - 30�C

  4. Boiling point 113�C and melting point - 90�C
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

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Multiple choice

The following table of properties was printed out for saturated liquid and saturated vapour of ammonia. The titles for only the first two columns are available. All that we know is that the other columns (columns 3 to 8) contain data on specific properties, namely, internal energy (kJ/kg), enthalpy (kJ/kg) and entropy (kJ/kg.K).

             
T(0C)
P(kPa)

||||||| | -20 | 190.2 | 88.76 | 0.3657 | 89.05 | 5.6155 | 1299.5 | 1418.0 | | 0 | 429.6 | 179.69 | 0.7114 | 180.36 | 5.3309 | 1318.0 | 1442.2 | | 20 | 857.5 | 272.89 | 1.0408 | 274.30 | 5.0860 | 1332.2 | 1460.2 | | 40 | 1554.9 | 368.74 | 1.3574 | 371.43 | 4.8662 | 1341.0 | 1470.2 |

When saturated liquid at 40°C is throttled to -20°C, the quality at exit will be

  1. 0.189

  2. 0.212

  3. 0.231

  4. 0.788
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

constant wall temperature conditions and for turbulent flow,Nu=0.023$Re^{0.8}$$Pr^{0.33}$

Multiple choice

The osmotic pressure of 5% sol of sucrose (M.M = 342) at 150 0 C, is

  1. 5.07 atm

  2. 5.007 atm

  3. 50.07 atm

  4. 500.07 atm
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The 5 % sol of sucrose means that 100 cm3 of sol contains 5 g of sucrose. Here, WB = 5 g, MB = 342 n mol-1, T = 150 + 273 = 423K, V = 0.100L, R = 0.082L atm mol-1K-1$\pi$  = nB/V RT = WBRT/MBRT =  5x0.082x423/342x0.100 = 5.07 atm

Multiple choice chemistry chemical equilibrium equilibrium in physical processes introduction to equilibrium chemical equilibrium and acids-bases

At what temperature liquid water will be in equilibrium with water vapour?
$\Delta H _{vap} = 40.73 \ kJ \ mol^{-1}$, $\Delta S _{vap} = 0.109 \ kJ \ K^{-1} \ mol^{-1}$, 

  1. 282.4 K

  2. 373.6 K

  3. 100 K

  4. 400 K
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The given reaction is :-

               ${ H } _{ 2 }O\left( l \right) \rightleftharpoons { H } _{ 2 }O\left( g \right) $
Now, at equilibrium, $\triangle G=0$
Now, from fibb's free energy change equation
         $\triangle G=\triangle H-T\triangle S$
$\Rightarrow \quad \triangle H=T\triangle S$
$\Rightarrow \quad T=\dfrac { \triangle H }{ \triangle S } =\dfrac { 40.73 }{ 0.1079 } =373.6K$
$\left( \because \triangle Hrap=40.73KJ/mol,\quad \triangle Srap=0.109KJ{ K }^{ -1 }{ mol }^{ -1 } \right) $

Multiple choice methods of purification of organic compounds methods of purification - organic compounds organic chemistry - some basic principles and techniques organic chemistry : some basic principles and techniques chemistry biochemical techniques

 A mixture of two immiscible liquids chlorobenzene and water boils at $90^{0}C$ and an external pressure of 740.2 torr. If vapour pressure of pure water at $90^{0}C$ is 530 torr then the mole % of chlorobenzene in the distillate will be:

  1. 80%

  2. 40%

  3. 28%

  4. 60%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Using Dalton's law for steam distillation: P_total = P_water + P_chlorobenzene. 740.2 = 530 + P_chlorobenzene, so P_chlorobenzene = 210.2 torr. The mole ratio n_c/n_w = P_c/P_w = 210.2/530 = 0.396. Mole fraction of chlorobenzene = 0.396 / (1 + 0.396) = 0.283, or 28%.

Multiple choice polyhalogen compounds haloalkanes and haloarenes chemistry

0.0852 g of an organic halide (A) when dissolved in 2.0 g of camphor, the melting point of the mixture was found to be $167^{\circ}$C. Compound (A) when heated with sodium gives a gas (B). 280 mL of gas (B) at STP weighs 0.375g. What would be 'A' in the whole process? $K _f$ for camphor = 40, m.pt. of camphor = $179^{\circ}$C.

  1. $C _2H _5Br$
  2. $CH _3I$
  3. $(CH _3) _2CHI$
  4. $C _3H _7Br$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$\delta$=179-167=12, w=0.0852g, W=2g,Kf= 40 
Moleculer weight of (A)
=$\dfrac{1000\times{Kf}\times{w} }{\delta{T}\times {W}}$
=$\dfrac{1000\times{40}\times{0.0852} }{\delta{12}\times {2}}$
=142
(A) undergoes wortz reaction to form (B) i.e
$(A)\rightarrow{Na} (B)+NaX$
(B) is an alkane say $C _nH _2n+2$
$\therefore$ 280 mL of (B) weighs 0.375 g at NTP
$\therefore$ 22400 mL of (B) weighs 
=$\dfrac{0.375\times{22400}}{280}$
=30 g at NTP
M.wt of (B)=30, 12n+2n+2=30,n=2
Thus (B) is ethane and therefore (A) is $CH _3X$
The m.wt of $CH _3X$=142
At.wt of X=127
$\therefore$ is iodine 
Therefore alkyl halide is $CH _3I$.
This reaction is 
2$CH _3I\xrightarrow[Na]{ether} C _2h _6$
(A)                         (B)

Multiple choice c3, c4 and cam plants photosynthesis in higher plants biology

The saturation point of $CO _2$ in $C _4$ plants is?

  1. $390$ $\mu l/L$
  2. $450$ $\mu l/L$
  3. $460$ $\mu l/L$
  4. $360$ $\mu l/L$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

C4 plants are highly efficient at capturing CO2 and reach their photosynthetic saturation point at lower concentrations compared to C3 plants, typically around 360 microliters per liter.

Multiple choice chemistry lattice energy defining lattice energy ionic or electrovalent bond energy cycles

Boiling point of a substance is based on the intermolecular and intramolecular forces which in turn determine the lattice energy of a substance.
Which of the following substance would have the highest boiling point?

  1. $NaCl$
  2. $Hg$
  3. $AlF _{3}$
  4. $H _{2}O$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$NaCl$ will have the highest boiling point as it is the strongest ionic compound present in the given options. $NaCl$ have strong interionic forces as $Na^+$ and $Cl^-$ attracts each other very strongly which results in an increase in the compactness of the molecule, further its lattice enthalpy.

Multiple choice chemistry materials liquid crystals liquid state the liquid state

$510 mg$ of a liquid on vaporization in victor Mayer's apparatus displaces $67.2 ml$ of dry air (at NTP). The molecular weight of liquid is:

  1. $130$
  2. $17$
  3. $1700$
  4. $170$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

As we know that $1g$ mole of any gas occupies as $22400ml$ of volume at STP

So molecular mass of compound= $\cfrac {0.510\times 22400}{67.2}$
$\Rightarrow 16.999 \approx 17$