Tag: chemistry

Questions Related to chemistry

What is the color of $ {P}{Cl} _{3} $ ?

chemistry p- block elements-ii compounds of phosphorus - pcl3 phosphorus halides compounds of phosphorus compounds of phosphorus- pcl5

  1. White

  2. Colorless

  3. Brown

  4. Bright yellow

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Correct Option: B
Explanation:

${P}{Cl} _{3}$ is a colorless liquid or has a slight yellow color (but not bright yellow).

Is ${PCl} _{3}$ soluble in water?

chemistry p- block elements-ii compounds of phosphorus - pcl3 phosphorus halides compounds of phosphorus compounds of phosphorus- pcl5

  1. Not Soluble

  2. May be

  3. Partially soluble

  4. Soluble

Show answer
Correct Option: D
Explanation:
like dissolve like. It means polar molecules dissolves in polar molecules and non-polar molecules.Molecules dissolves in non polar molecules $Water$ and $PCl _3$ both are polar molecules because of their shape and electronegative difference between $H$ and $O$ in water and $P$ and $Cl$ in $PCl _3$. Hence $PCl _3$ is solube in water.
$PCl _3$ dissolve in water to form phosphorous acid.
$PCl _3$ $+$ $3H _2O$  $\longrightarrow $   $H _3PO _3$ $+$ $3HCl$

What is the odor of $ {P}{Cl} _{3}$ ?

chemistry p- block elements-ii compounds of phosphorus - pcl3 phosphorus halides compounds of phosphorus compounds of phosphorus- pcl5

  1. Pungent

  2. Fishy

  3. Sweet

  4. None of the above

Show answer
Correct Option: A
Explanation:

Phosphorus trichloride is prepared from phosphorus and chlorine. It has a pungent and irritating odour that is similar to that of hydrochloric acid.

What is the density of ${PCl} _{3}$?

chemistry p- block elements-ii compounds of phosphorus - pcl3 phosphorus halides compounds of phosphorus compounds of phosphorus- pcl5

  1. $2.0 g/cc$

  2. $2.g/cc$

  3. ${1.57g/cc}$

  4. $3.0g/cc$

Show answer
Correct Option: C
Explanation:

The density of phosphorus trichloride is ${1.57}$ ${gm}{/}{cm}^{3}$

How is $ {P}{Cl} _{3} $ produced industrially?

chemistry p- block elements-ii compounds of phosphorus - pcl3 phosphorus halides compounds of phosphorus compounds of phosphorus- pcl5

  1. Reacting chlorine with white phosphorus

  2. Reacting chlorine with phosphorus acid

  3. Reacting chlorine with black phophorous

  4. All of the above

Show answer
Correct Option: A
Explanation:
Industrially Phosphorous trichloride is prepared by the reaction of Chlorine with a solution of white Phosphorous in phosphorous trichloride.
The reaction is given by:
$P _4$ $+$ $6Cl _2$ $\longrightarrow $ $4PCl _3$

What is the structure of phosphorus trichloride?

chemistry p- block elements-ii compounds of phosphorus - pcl3 phosphorus halides compounds of phosphorus compounds of phosphorus- pcl5

  1. Trigonal Pyramidal

  2. Trigonal Planar

  3. Tetrahedral

  4. Square Planar

Show answer
Correct Option: A
Explanation:

In ${ PCl } _{ 3 }$, $P$ is ${ sp }^{ 3 }$ hybridized with a lone pair. This makes its structure trigonal pyramidal. So, the correct answer is option $A$.

What is the physical state of ${PCl} _{3}$ under normal condition?

chemistry p- block elements-ii compounds of phosphorus - pcl3 phosphorus halides compounds of phosphorus compounds of phosphorus- pcl5

  1. Solid

  2. Liquid

  3. Gaseous

  4. None of these

Show answer
Correct Option: B
Explanation:

${PCl} _{3}$ is liquid under normal conditions. ${PCl} _{3}$ is a covalent compound. Phosphorus and each of the chlorine atoms fulfil their octet by mutually sharing their valence electrons. In general, covalent compounds have weak bond energy and hence they form liquid.

Dehydrated phosphorus trichloride in water gives:

chemistry p- block elements-ii compounds of phosphorus - pcl3 phosphorus halides compounds of phosphorus compounds of phosphorus- pcl5

  1. $H _3PO _3$

  2. $H _3PO _4$

  3. $H _3PO _2$

  4. none

Show answer
Correct Option: A
Explanation:

Dehydrated phosphorus trichloride in water gives phosphoric acid.

$PCl _3 + 3H _2O\rightarrow  H _3PO _3 + 3 HCl$

Hence option A is correct.

0.05 mole of $LiAlH _4$ in ether solution was placed in a flask containing 74g (1 mole ) of t-butyl alcohol.The product $LiAlHC _{12}H _{27}O _3$ weighed 12.7 g. If Li atoms are conserved, the percentage yield is : (Li=7, Al=27, H=1, C=12, O=16).

chemistry introduction to analytical chemistry interpreting a balanced chemical reaction percentage yield stoichiometric calculations

  1. 25%

  2. 75%

  3. 100 %

  4. 15 %

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Correct Option: C

$1.25$ g of sample of limestone on heating gives $0.44$ g carbon dioxide. The percentage purity of $CaCO _3$ in limestone is:

chemistry introduction to analytical chemistry interpreting a balanced chemical reaction percentage yield stoichiometric calculations

  1. $75\%$

  2. $85\%$

  3. $90\%$

  4. $80\%$

Show answer
Correct Option: D
Explanation:

$CaCO _3$ $\quad \underrightarrow \Delta\quad  CaO +CO _2$

Moles of $CO _2$ produced =$\cfrac{0.44}{44}$$=0.01$ moles
Moles of pure $CaCO$$ _3$ required $=0.01$ moles
$=0.01 \times 100g$
$=1g$
Therefore $\%$ purity of $CaCO$$ _3$  in limestone =$\cfrac{1}{1.25}\times 100$
$=80\%$