Explanation

- K₂Cr₂O₇ is a strong oxidizing agent commonly used to oxidize aldehydes to carboxylic acids.  

- HI and NaBH₄ are reducing agents, and NiH₄ is not typically used here.

Explanation

- With 4 electron pairs (3 bonding + 1 lone), the shape is trigonal pyramidal (e.g., NH₃).  

- Bent/angular shape occurs with 2 bond pairs + lone pairs.  

- Trigonal planar has 3 bond pairs and no lone pair.  

- Trigonal is incomplete — trigonal planar is correct term.

Explanation

Negative ΔH means heat is released, so reaction is exothermic.

Explanation

Coinage metals are Copper (Cu), Silver (Ag), and Gold (Au) due to their historical use in coins.  

- Pd (Palladium), Cd (Cadmium), and Hg (Mercury) are not coinage metals.

Explanation

Let the formula be XₐY_bZ_c.

Charge balance equation:  

(+6)·a + (-2)·b + (-1)·c = 0

 XY₂Z₂ → a=1, b=2, c=2  

Charge = (6×1) + (-2×2) + (-1×2) = 6 - 4 - 2 = 0 

Explanation

The not allowed set is:

n = 2, l = 2, m = 1, s = +1/2

Reason:  

- For a given principal quantum number n, the azimuthal quantum number l must satisfy:  

  0 ≤ l ≤ n - 1  

- Here, n = 2, so l can only be 0 or 1.  

- l = 2 is invalid for n = 2.

Explanation

- Reaction rate = change in concentration of reactants/products per unit time, adjusted by stoichiometric coefficients.

For the reaction:  

2A + 3B → C + D

Rate = - (1/2) d[A]/dt = - (1/3) d[B]/dt = d[C]/dt = d[D]/dt

- -d[B]/dt alone does not account for the stoichiometric coefficient (3), so it does not correctly express the rate.

Explanation

- Activation energy is the minimum energy required for reactant molecules to collide and break bonds, initiating a chemical reaction.  

- Bond energy is the energy required to break a specific bond in a molecule.

Explanation

Given:

- Reaction: 2H₂ + O₂ → 2H₂O  

- Mass of H₂ = 4 g  

- Mass of O₂ = 32 g  

- Mass of H₂O produced = 28 g  

- Molar masses: H₂ = 2 g/mol, O₂ = 32 g/mol, H₂O = 18 g/mol

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Step 1: Calculate moles of reactants

- Moles of H₂ = 4 g ÷ 2 g/mol = 2 mol  

- Moles of O₂ = 32 g ÷ 32 g/mol = 1 mol

Step 2: Determine the limiting reagent

- According to the balanced equation, 2 mol H₂ react with 1 mol O₂.  

- Both are in the exact stoichiometric ratio, so neither is limiting.

Step 3: Calculate theoretical yield of H₂O

- 2 mol H₂ produce 2 mol H₂O (1:1 molar ratio)  

- Moles of H₂O = 2 mol  

- Mass of H₂O = 2 mol × 18 g/mol = 36 g (theoretical yield)

Step 4: Calculate percentage yield

- Percentage yield = (Actual yield / Theoretical yield) × 100  

- = (28 g / 36 g) × 100 = 77.8%

Explanation

- Lipase breaks down lipids (fats) into fatty acids and glycerol.  

- Amylase acts on starch, Protease on proteins, and Urease on urea.