The p-Block Elements - Online Test
Q1. Ammonia act as a Lewis base because nitrogen has
Q2. Which allotrope of phosphorous is most stable?
Answer : Option A
Explaination / Solution:
Black Phosphorus is most stable isotope of phosphorus because it is highly polymerized form of phosphorous.
Q3. At what temperature white phosphorous changes to red phosphorous?
Answer : Option D
Explaination / Solution:
White phosphorus when heated to 573 K in an inert atmosphere for several days red Phosphorus is obtained.
Q4. What is the spontaneous ignition temperature of white phosphorous?
Answer : Option A
Explaination / Solution:
Ignition temperature of white phosphorus is 35 oC
Q5.
is the structure of
is the structure of
Answer : Option D
Explaination / Solution:
This structure is of H3PO4 . (Orthophosphoric acid). It has three P-OH and one P=O bonds.
Q6.
is the structure of
is the structure of
Answer : Option C
Explaination / Solution:
H3PO2 is Hypophosphorus acid. It has one P-OH, two P-H and one P=O bonds.
Q7. Elements of which group are known as ore forming elements?
Answer : Option D
Explaination / Solution:
Maximum number of ores contain group16 elements (O, S etc). They are known as "chalcogens" which was derived from the Greek word chalcos , meaning "ore formers," since they all are be found in copper ores.
Q8. Most metal oxides are
Answer : Option B
Explaination / Solution:
In general, metal oxides are basic and ionic in nature.
Q9. The thermal stability of hydrides of group 16 elements decreases in the order
Answer : Option A
Explaination / Solution:
As we move down the group bond length increases and bond enthalpy for the dissociation of H-E bond decreases. Due to decrease in enthalpy the thermal stability of hydrides decreases down the group.
Q10. Formula of oleum is
Answer : Option B
Explaination / Solution:
Oleum is pyrosulphuric acid (H2S2O7 )
