Class 11th

11.47 The state of hybridisation of B in BH₄ is

(a) sp (b) sp² (c) sp³ (d) None

11.46 What is producer gas?

(a) mixture of CO and N₂ in the ratio of 2 :1

(b) mixture of CO and N₂ in the ratio of 1 :1

(c) mixture of CO and N₂ in the ratio of 1 :2

(d) mixture of CO and N₂ in the ratio of 3 :1

11.45 Anhydride of carbonic acid is:

(a) H₂CO₃  (b) CO₃  (c) CO^-  (d) CO₂

MCQs

11.44 Which of the following statement is incorrect?

(a) Non-metals and metalloids exist only in the p-block of the periodic table.

(b) The non-metallic character of elements decreases down the group.

(c) The change of non-metallic to metallic character can be best illustrated by the nature of oxides they form.

(d) The non-metal oxides are basic whereas metal oxides are acidic or neutral in nature

11.43. Assertion: Boron halides form addition compounds with NH₃.

Reason: Boron halides are Lewis bases.

11.42. Assertion: Heavier elements form pπ– pπ bonds.

Reason: Their atomic orbitals are too large and diffuse to have effective overlapping.

Assertion and Reason:

Directions:

(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.

(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.

(c) Assertion is correct statement but reason is wrong statement.

(d) Assertion is wrong statement but reason is correct statement.

11.39. Assertion: Non-metals readily form anions, in contrast to metals whichreadily form cations. 

Reason: In general, non-metals have higher ionisation enthalpies and higherelectronegativities than the metals.

43. Evaluate ${\displaystyle \sum _{k=1}^{11}}\left(2+3^x\right).$

41. 1, – a, a², – a³, . n terms (if a ¹ – 1).

40. √7 , √21 , 3√7  , . n terms.