Explanation

Three classes of magnetic materials are

(i) Diamagnetic

(ii) Paramagnetic

(iii) Feromagnetic

Correct Answer: A. Human resources

Correct Answer: B. rebuked

Correct Answer: A. the protagonist

Correct Answer: B. presidentialism

Explanation

(a)(i) Is the energy required to remove one mole of an electron from a gaseous atom.

OR

Is the minimum energy required to convert one mole of a gas of atom into one mole of a gaseous plus 1 ions

(ii) \(_{4}\)Be: Is\(^{2}\) 2s\(^{2}\)

\(_{5}\)B :Is\(^{2}\) 2s\(^{2}\) 2p\(^{1}\)

The electron to be removed from Be is in the 2s orbital which is closer to the nucleus, nuclear attraction is greater hence first ionization energy is greater but the electron to be removed from B is in the 2p orbital which is farther away from the nucleus, hence nuclear attraction is weaker hence first ionization energy is smaller.

OR

2p has less energy than 2s

So it is easier to remove an electron from 2p as the nuclear charge is weaker in 2p because 2p is further away from the nucleus. Hence, first ionization energy is small.

(b) Q - It

Q = 0.12 x 500

= 60 C

96500 = 1F

= 60 C liberates 0.015g

\(\therefore\) 96500 will liberate \(\frac{96500}{60}\) x 0.015

= 24 g

n((T\(_{1}\)) = \(\frac{m}{M}\)

= \(\frac{24}{48}\) = 0.5mol

1F = 0.5mol

2F = 1mol

hence charge = +2

Alternative A

Q = lt

= 0.12 x 500

= 60 C

0.015 g of Ti is deposited by 60 C .

\(\therefore\) 48 g will be deposited by = \(\frac{60}{0.015}\) x 45

= 1920000

96500 C\(\equiv\) i mole of electron

\(\therefore\) 192000 C \(\frac{1}{96500}\) x 192

= 1.989

\(\approx\) 2.0 moles of electron

\(\therefore\) charge on Ti ion is +2

Alternate B

\(\frac{m}{M} = \frac{It}{nF}\)

n = \(\frac{Mlt}{mF}\)

= \(\frac{48 \times 0.12 \times 500}{0.015 \times 96500}\)

= 1.989 \(\equiv\) 2

\(\therefore\) Change on Ti ion is +2

(c)(i) Alumina (Al\(_{2}\)\(_{3}\)) mixed with molten cryolite (Na\(_{3}\)AIF\(_{6}\))

(i) - abundant deposits of bauxite

- cheap source of electricity

(d)(i) Is the ability of a substance to be attracted strongly into a magnetic field.

(ii) I. \(_{24}\)Cr\(^{2+}\) - Is\(^{2}\) 2P\(^{6}\) 3S\(^{2}\) 3P\(^{6}\) 3d\(^{4}\)

unpaired electrons = 4

\(_{24}\)Cr\(^{6}\) - Is\(^{2}\) 2s\(^{2}\) 2p\(^{6}\) 3s\(^{2}\) 3d\(^{6}\)

unpaired electrons = 0

(II) \(_{24}\)Cr\(^{2+}\)

III. The greater the number of unpaired electrons in the 3d - orbital, the| greater-the paramagnetism.

Correct Answer: D. opinion sampling

Explanation

An opinion poll/sampling, often simply referred to as a poll or a survey, is a human research survey of public opinion from a particular sample.

Correct Answer: C. Malachi

Correct Answer: D) Coverage

Explanation

The options given are Mobility, Cost, Stability, and Coverage. Mobility refers to the ability to move around while still being able to make calls and send messages. Cost refers to how much it costs to use the GSM network. Stability refers to how reliable the network is, and whether it experiences problems or interruptions. Coverage refers to the extent of the network's reach, and how many areas it can cover.

Out of these options, the correct answer is Coverage. This means that GSM has an advantage over other mobile networks because it has a wider reach and can cover more areas. This is important because it means that people in more remote or rural areas can still use the GSM network to make calls and send messages.

In summary, the distinctive advantage of GSM is its coverage. This means that the GSM network can cover more areas and reach more people than other mobile networks. This is important for people who live in areas that might not be covered by other networks.

Correct Answer: B) 5g of marble powder at 50°C

Explanation

Marble is a form of calcium carbonate (CaCO₃) and reacts with hydrochloric acid (HCl) to produce calcium chloride (CaCl₂), water (H₂O), and carbon dioxide (CO₂). The reaction can be represented as:

\(CaCO_3 + 2HCl \rightarrow CaCl_2 + H_2O + CO_2\)

There are several factors that can affect the rate of this reaction, including temperature, concentration, and surface area of the reactants. In the given options, we can see that the surface area and temperature are the variables being manipulated.

Option A and Option D involve marble lumps, which have a smaller surface area compared to marble powder. A smaller surface area means less contact between the reactants, leading to a slower reaction rate.

Option B and Option C involve marble powder, which has a larger surface area compared to marble lumps. A larger surface area allows for more contact between the reactants, leading to a faster reaction rate.

Temperature also plays a role in the reaction rate. As temperature increases, the kinetic energy of the molecules increases, leading to more frequent and energetic collisions between reactants. This results in a faster reaction rate. Option B has a higher temperature (50^oC) compared to Option C (25^oC), and thus will have a faster reaction rate.

Considering both surface area and temperature,Option B: 5g of marble powder at 50^oC is the correct answer, as it has the largest surface area and the highest temperature, resulting in the fastest reaction rate.