When ammonium hydroxide NH₄OH is treated with iron (III) chloride solution, it produces a reddish brown precipitate of ferric hydroxide Fe(OH)₃, which is insoluble in excess of NH₄Cl.

6NH₄OH + 2FeCl₃ → 2Fe(OH)₃ + 6NH₄Cl

When methane (CH₄) undergoes complete combustion in oxygen (O₂), it produces carbon dioxide (CO₂) and water (H₂O).  The balanced chemical equation for this reaction is:

CH₄ (g) + 2O₂ (g) → CO₂ (g)+ 2H₂O (l)

CO₂

Explanation: Among the given greenhouse gases, CO₂ (carbon dioxide) has the maximum contribution to global warming.

(b)

Explanation: If you plot PV (product of pressure and volume) against P (pressure), the graph will be a horizontal straight line. This is because, according to Boyle's Law, the product of pressure and volume remains constant for a given amount of gas at a constant temperature.

d. C₂H₂

Explanation: Molecular Mass = 2 × Vapour Density

= 2 × 13 = 26

• Molecular Mass of CO₂ = 44
• Molecular Mass of C₂H₄ = 28
• Molecular Mass of C₂H₆ = 30
• Molecular Mass of C₂H₂ = 26

c. °C^-1

d. Virtual and erect

Explanation: When an object is placed between the optical center and the focus of a convex lens, the rays diverge after refraction, making them appear to originate from a point on the same side as the object. This results in a virtual, erect, and magnified image.

a. 0°

Explanation: When a ray of light is incident perpendicularly (at 90° to the surface) on a transparent glass slab, it passes through the slab without bending. Since there is no change in direction, the angle of deviation is 0°.

d. ohm

Explanation: The SI unit of electrical resistance is the ohm (Ω). It is defined as the resistance between two points of a conductor when a constant potential difference of one volt, applied to these points, produces a current of one ampere.

a. a stream of electrons

Explanation: β-rays (beta rays) emitted from a radioactive element consist of a stream of electrons. These electrons are high-energy, high-speed particles that are emitted during beta decay.

d. 18

Explanation: The long form of the periodic table has 18 groups. These groups are columns in the table where elements share similar chemical properties.

b. LiH

Explanation: In LiH (lithium hydride), the octet rule is not obeyed because lithium requires only 2 electrons to achieve a stable configuration (duet rule), and hydrogen also needs just 2 electrons.