Tag: chemistry

Questions Related to chemistry

Which of the following is a source of instant energy?

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Salt

  2. Glucose

  3. Water

  4. Starch

Show answer
Correct Option: B
Explanation:

Glucose is a source of instant energy because it is quick to act to create energy along with oxygen so our body does not need to convert the glucose to anything else. It also can be absorbed through the lining of the stomach.

The products formed when a pinch of sugar is strongly heated for fifteen minutes in a test tube are:

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. carbon and water vapour

  2. carbon, hydrogen and oxygen

  3. carbon dioxide and water vapour

  4. carbon dioxide and hydrogen

Show answer
Correct Option: C
Explanation:

Any carbohydrate will give water and $CO _2$ after combustion.

Example: Combustion of Glucose,
$C _6H _{12}O _6 + 6O _2 \xrightarrow{heat} 6CO _2 +6 H _2O$

When sugar is treated with sulphuric acid, we get a very pure form of:

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. carbon

  2. oxygen

  3. water

  4. hydrogen

Show answer
Correct Option: A
Explanation:

(A) carbon

Concentrated sulphuric acid is a strong dehydrating agent. Sulphuric acid removes water from organic compounds; it is evident by its charring action on carbohydrates.
${C} _{12}{H} _{22}{O} _{11} \xrightarrow{\text{ conc. } {H} _{2}S{O} _{4}} 12C + 11{H} _{2}O$

Transition state structure of the substate formed during an enzymatic reaction is

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Transient but stable

  2. Permanent but unstable

  3. Transient and unstable

  4. Permanent and stable

Show answer
Correct Option: C
Explanation:

Transition state is intermediate state produced during enzymatic biochemical reaction which is transition state and unstable state

Which enzyme converts glucose to ethanol?

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Diesterase

  2. Invertase

  3. Zymase

  4. Both (2) and (3)

Show answer
Correct Option: C
Explanation:

$Glucose\underrightarrow { Zymase } Ethanal$
Zymase converts glucose to ethanal

The light coming from the sun is stored as energy in plants by the process of photosynthesis. This happens by converting carbon dioxide and water into:

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. green leaves

  2. carbohydrates

  3. fats

  4. plants hormones

Show answer
Correct Option: B
Explanation:

Photosynthesis is the process by which plants utilize the energy from the sunlight in order to convert carbon dioxide and water into carbohydrates.

Formula of glucose is :

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. $C _{5}H _{12}O _{6}$

  2. $C _{6}H _{12}O _{16}$

  3. $C _{6}H _{12}O _{7}$

  4. $C _{6}H _{12}O _{6}$

Show answer
Correct Option: D
Explanation:

Formula of glucose is $C _6H _{12}O _6$ it is derived from the reaction of photosynthesis that is :


$6CO _2 + 6H _2O \overset{Sunlight}\longrightarrow C _6H _{12}O _6 + 6O _2$

Hence, the correct option is D.

Which of the following compounds will not undergo decomposition on passing electricity through aqueous solution?

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Sugar

  2. Sodium chloride

  3. Sodium bromide

  4. Sodium acetate

Show answer
Correct Option: A
Explanation:

Sodium chloride, sodium bromide, and sodium acetate are all ionic compounds and hence, they dissociate into their respective ions in an aqueous solution. On the contrary, sugar is a covalent compound and hence does not dissociate into ions

The two functional groups present in a typical carbohydrate are :

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. $-CHO$ and $-COOH$

  2. $-CO$ and $-OH$

  3. $-OH$ and $-CHO$

  4. $-OH$ and $-COOH$

Show answer
Correct Option: B
Explanation:

Carbohydrates are polyhydroxy aldehydes or polyhydroxy ketones OR compounds which give aldehydic as well as ketonic groups on hydrolysis. Therefore the major functional groups are (carbonyl) Aldehyde, Ketone, and hydroxy groups. 

Out of $1$M glucose and $2$M glucose. 2M glucose has  a higher boiling point.

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

2 M glucose has a higher boiling point than 1 M of glucose.

Since on increasing the no of moles the molality also increases which is directly proportional to an elevation in boiling point.
Thus, the boiling point of the 2M of glucose will be greater than 1M glucose.