Question Discussion & Solution

The correct answer is ​Red and yellow soil.

Key Points

• Red and Yellow Soil:
  • Red soil develops on crystalline igneous rocks in areas of low rainfall in the eastern and southern part of the Deccan Plateau. Hence option 1 is correct.
  • Along the piedmont zone of the Western Ghat, a long stretch of area is occupied by red loamy soil.
  • Yellow and red soils are also found in parts of Odisha and Chhattisgarh and in the southern parts of the middle Ganga plain.
  • The soil develops a reddish colour due to a wide diffusion of iron in crystalline and metamorphic rocks.
  • It looks yellow when it occurs in a hydrated form.
  • The fine-grained red and yellow soils are normally fertile, whereas coarse-grained soils found in dry upland areas are of poor infertility.
  • They are generally poor in nitrogen, phosphorous and humus.

Valency is the combining power of an element. Elements in the same group of the periodic table have the same valency.

Key Points

• Valency is the no of electron that looses, shared or gain to achieve stability or we can say to complete it outer most shell. 
• If any element has valence electron (electrons present in outer most shell) less than 4
  • ​​Valency = no of valance electron (valence electron<4)
• If any element has valence electron ​more than 4
  • ​​Valency = 8 - no of valance electron (valence electron>4)

​For Lithium:

• Li(Z=3) Electronic configuration = 2, 1
  • Valency = no of valance electron  = 1

​Hence, we can conclude that 1 is the valency of Lithium.

Let the three consecutive numbers be x, x + 1, x + 2

⇒ x + (x + 1) + (x + 2) = 345

⇒ 3x + 3 = 345

⇒ 3x = 345 – 3 = 342

\(\Rightarrow x = \frac{{342}}{3} = 114\)

So the three consecutive numbers are 114, 115 and 116. And the middle number is 115.

Concept: To find out the cube of the next number.

Solution:

From the given figure, it can be seen-
1³ = 1

2³ = 8

3³ = 27

4³ = 64

5³ = 125

6³ = 216

So, the number is 216.

Given series: 2, 5, 10, 17, 26, 37, 50, 65, 82, _________

The logic is:

2 + 3 = 5

5 + 5 = 10

10 + 7 = 17

17 + 9 = 26

26 + 11 = 37

37 + 13 = 50

50 + 15 = 65

65 + 17 = 82

82 + 19 = 101