Tag: chemistry

Quizzes (490) Questions (9892)

Questions Related to chemistry

Multiple choice chemistry air environment and pollution environment pollution for a pollution free nature

Which of the following is not regarded as a pollutant?

  1. $NO _{2}$
  2. $CO _{2}$
  3. $SO _{2}$

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

Pollutants can be classified as solid, gaseous or liquid pollutants. Also, it can be classified as physical, chemical and biological. They can be further classified as degradable and non-degradable. $NO _2$, $SO _2$  and CO are gases which if present in great quantity in the atmosphere can cause pollution.

Multiple choice chemistry air environment and pollution environment pollution for a pollution free nature

Match the column I with column II and mark the appropriate choice.

Column I Column II
(A) Biodegradable pollutants (i) DDT
(B) Non-biodegradable pollutants (ii) $SO _{2}$
(C) Primary pollutants (iii) PAN
(D) Secondary pollutants (iv) Sewage
  1. (A) $\rightarrow$ (iii), (B) $\rightarrow$ (iv), (C) $\rightarrow$ (ii), (D) $\rightarrow$ (i)
  2. (A) $\rightarrow$ (ii), (B) $\rightarrow$ (iii), (C) $\rightarrow$ (iv), (D) $\rightarrow$ (i)
  3. (A) $\rightarrow$ (i), (B) $\rightarrow$ (ii), (C) $\rightarrow$ (iii), (D) $\rightarrow$ (iv)
  4. (A) $\rightarrow$ (iv), (B) $\rightarrow$ (i), (C) $\rightarrow$ (ii), (D) $\rightarrow$ (iii)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Sewage is a biodegradable pollutant which can be degraded. DDT is a type of non biodegradable pollutant. $ S0 _2 $ is a primary pollutant, affecting the environment. PAN is considered as a secondary pollutants among all the pollutants. 

Multiple choice chemistry air environment and pollution environment pollution for a pollution free nature

Match the upper limit concentration of the pollutants given in column I with column II and mark the appropriate choice.

Column I Column II
(A) Lead (i) 500 ppm
(B) Sulphate (ii) 10 ppm
(C) Nitrate (iii) 50 ppb
(D) Fluoride (iv) 50 ppm
  1. (A) $\rightarrow$ (ii), (B) $\rightarrow$ (iii), (C) $\rightarrow$ (i), (D) $\rightarrow$ (iv)
  2. (A) $\rightarrow$ (iii), (B) $\rightarrow$ (i), (C) $\rightarrow$ (iv), (D) $\rightarrow$ (ii)
  3. (A) $\rightarrow$ (i), (B) $\rightarrow$ (iv), (C) $\rightarrow$ (iii), (D) $\rightarrow$ (ii)
  4. (A) $\rightarrow$ (iv), (B) $\rightarrow$ (ii), (C) $\rightarrow$ (iii), (D) $\rightarrow$ (i)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The concentration of pollutants like lead is 50 ppb. So the water gets contaminated with lead. The concentration of sulphate is 500 ppm. The concentration of nitrate is 50 ppm. Concentration of fluoride is 10 ppm. 

Multiple choice chemistry air environment and pollution environment pollution for a pollution free nature

The pollutants which come directly in the air from sources are called primary pollutants. Primary pollutants. Which of the following belongs to secondary air pollutants? 

  1. $CO$
  2. $Hydrocarbon$
  3. $Peroxyacetyle\ nitrate\ (PAN)$
  4. $NO$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
The correct answer is NO (nitrogen oxide) which reacts with oxygen to form nitrogen dioxide, participate in a complex of ultraviolet-driven photochemical reactions. and it also forms acid rain when it reacts with water.
Multiple choice chemistry alcohols, esters and carboxylic acids reduction of carboxylic acids chemical properties chemical properties of carboxylic acids

$PhCOOH\xrightarrow{DIBALH} $ 

  1. $PhCHO$
  2. $PhO$
  3. $PhCH _2OH$

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Benzoic acid on reduction with di-isobutyl aluminium hydride (DIBALH) gives benzaldehyde.
$\displaystyle PhCOOH \xrightarrow {DIBALH} PhCHO $
Di-isobutyl aluminium hydride (DIBALH) is a reducing agent. It reduces carboxylic acids to aldehydes.

Multiple choice chemistry alcohols, esters and carboxylic acids reduction of carboxylic acids chemical properties chemical properties of carboxylic acids

How  - $COOH$ can be converted into $CH _3$ group?

  1. $\;Na\;\&\;alcohol$
  2. $\;Zn+HCl$
  3. $\;LiAlH _4$
  4. $\;Hl\;\&\;red\;phosphorous$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$-COOH$ can be converted into $CH _3$ group by heating with a mixture of HI and red phosphorus.
$CH _3COOH  \xrightarrow {\;Hl\;&\;red\;phosphorous} CH _3-CH _3$

Multiple choice chemistry alcohols, esters and carboxylic acids reduction of carboxylic acids chemical properties chemical properties of carboxylic acids

Which of the following reaction is not the oxidation?

  1. $CH _{3} - CHO \rightarrow CH _{3}COOH$
  2. $C _{2}H _{5}OH \rightarrow CH _{3} - CHO$
  3. $C _{2}H _{5}OH \rightarrow CH _{3} - COOH$
  4. $CH _{3}COOH \rightarrow C _{2}H _{5}OH$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Oxidation involves the loss of electrons or an increase in oxidation state (often adding oxygen or removing hydrogen). Option D shows the reduction of acetic acid to ethanol (adding hydrogen), which is the opposite of oxidation.