Write with a balanced chemical equation what happens when an aqueous solution of ammonia is added to an aqueous solution of ferric chloride. [External Candidate]
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
Question ID: 104
Uploaded on: September 14, 2024
Write with a balanced chemical equation what happens when methane undergoes combustion in oxygen. [External Candidate]
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)
Question ID: 105
Uploaded on: September 14, 2024
Which of the following greenhouse gasses has the maximum contribution towards global warming?
CO2
Explanation: Among the given greenhouse gases, CO2 (carbon dioxide) has the maximum contribution to global warming.
Question ID: 106
Uploaded on: September 15, 2024
According to Boyle’s law which is the PV vs P graph?
(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.
Question ID: 107
Uploaded on: September 15, 2024
If the vapour density of a carbon-containing gaseous substance is 13, which of the following can be its molecular formula?
d. C2H2
Explanation: Molecular Mass = 2 × Vapour Density
= 2 × 13 = 26
Question ID: 108
Uploaded on: September 15, 2024
The unit of coefficient of linear expansion of a solid is
c. °C-1
Question ID: 109
Uploaded on: September 15, 2024
An object is placed in between the optical centre and the focus of a thin convex lens. What is the nature of the image of the object?
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.
Question ID: 110
Uploaded on: September 15, 2024
When a ray of light is incident perpendicularly on a transparent glass slab, what will be its angle of deviation?
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°.
Question ID: 111
Uploaded on: September 15, 2024
Which of the units given below is the SI unit of resistance?
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.
Question ID: 112
Uploaded on: September 15, 2024
β-ray emitted from a radioactive element is
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.
Question ID: 113
Uploaded on: September 15, 2024
How many groups are in the long periodic table
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.
Question ID: 114
Uploaded on: September 15, 2024
In formation of which of the following compounds octet rule is not obeyed?
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.
Question ID: 115
Uploaded on: September 15, 2024