Classification Of Elements And Periodicity In Properties Ques 301
Question: A, B and C are hydroxy compounds of the elements P, Q and R respectively. P, Q and R are in the same period of the periodic table. A gives an aqueous solution of $ pH>7 $ . B reacts with both strong acids and strong alkalies. C gives an aqueous solution which is strongly alkaline. Which of the following statement(s) is/are true'
I. All the three elements are metals. II. The atomic radius decreases in the order P, Q, R. III. The electron negativities decrease from P to Q to R. IV. P, Q and R could be $ P,Al $ and Na respectively.
Options:
A) I, II and IV
B) III and IV only
C) II, III and IV
D) All are correct
Show Answer
Answer:
Correct Answer: B
Solution:
[b] Idea Students are advised to solve the problem by using the concept of nature of hydroxides of element and electronegativity of elements. [Keep in mind the all elements in 3rd period and their electronegativity order] (iv) Na, P and Al all the three belong to (iii) period. (iii) Electronegativities of P < Q < R Hydroxy compound of phosphorous $ =H_3PO_4=A $ (which is acidic so $ pH<7 $ ) $ Al{{(OH)}_3} $ is amphoteric in nature $ =B $ $ NaOH $ is strongly alkaline $ =C $
