JEE Main Test 146

Calculation:

Given air resistance is not ignored. Taking downward as positive y direction.

Equation of motion for upward motion,

Solving the equation gives us an exponential function i.e a function which is not linear

Hence, the fourth graph is most appropriate.

Concept:

Heisenberg’s Uncertainty Principle:

• W Heisenberg a German physicist in 1927, stated the uncertainty principle which is the consequence of dual behavior of matter and radiation.
• It states that it is impossible to determine simultaneously, the exact position and exact momentum (or velocity) of an electron.

CONCEPT:

Identification of Functional Groups

• The reagents used in qualitative analysis help detect specific functional groups in organic compounds.
• Each reagent reacts with certain functional groups, leading to distinct observations that help identify the functional group present.
• The following steps are involved in functional group detection:
  • React the compound with a specific reagent.
  • Observe color changes, precipitates, or other reactions.
  • Draw inferences based on known reactions of functional groups.

EXPLANATION:

• A. Alkaline solution of copper sulphate and sodium citrate: This reagent is used to detect phenols. It gives a characteristic blue-violet coloration with phenolic compounds.
• B. Neutral FeCl₃ solution: This test is also used to detect phenolic groups, which turn violet in color in the presence of FeCl₃.
• C. Alkaline chloroform solution: This reagent reacts with aldehydes to give a characteristic yellow or orange precipitate.
• D. Potassium iodide and sodium hypochlorite: This reagent detects alcohol groups by oxidizing them to aldehydes or ketones.

(A) Fehling’s solution is used to distinguish between aldehyde and ketone functional groups. Aldehydes oxidize to give a positive result but ketones won’t react to the test (except for a-hydroxy ketones). Fehling’s test is used as a general test for determining monosaccharides and other reducing sugars.

(C) This reaction is a chemical test for detection of primary amines, in which the amine is heated with alcoholic potassium hydroxide and chloroform. If a primary amine is present, the isocyanide is formed. The reaction is known as carbylamine reaction.

RNH₂ + CHCl₃ + 3KOH → RN⁺ ≡ C^– + 3KCl + 3H₂O

When a methyl ketone (even acetaldehyde) is reacted with halogen in aqueous sodium hydroxide, the ketone gets oxidised to the sodium salt of acid with one carbon less than ketone and at the same time haloform (CHX₃) also gets formed.

The hydroxide ion acts as a nucleophile and attacks the electrophilic carbon which is doubly bonded to oxygen. This carbon-oxygen double bond becomes a single bond making the oxygen atom anionic.

Correct answer: 3)

Concept:

• The pH of a solution is a measure of hydrogen ion concentration, which in turn is a measure of its acidity.
• Pure water dissociates slightly into equal concentrations of hydrogen and hydroxyl (OH⁻) ions.
• To calculate the pH of an aqueous solution you need to know the concentration of the hydronium ion in moles per liter (molarity).
• The pH is then calculated using the expression: pH = - log [H₃O⁺].

Explanation:

CH₂NH₂(base) on reaction with HCl to give salt of a weak base and strong acid as CH₃NH₃⁺Cl^-.

Concept: 

⇒  x - 2y + 6 = 0

We know that if a point is lying on a line, it will satisfy the equation of that line.

 Except point (5,4), all the points (0,3),(-6,0) and (4,5) are lying on the line x-2y+6=0.

Therefore, the correct answer is (5,4).