Answer:
The correct answer is: X is nitrogen dioxide, and Y is a metal oxide
Explanation:
Combustion of compound of containing nitrogen and metal will give nitrogen dioxide and metal oxide as product. During combustion reaction a compound reacts with oxygen in order to yield oxides of elements present in the compound.
The general equation is given as:

Hence, the correct answer is :X is nitrogen dioxide, and Y is a metal oxide.
Answer:
100ml of a stock 50% KNO3 solutions are needed to prepare 250ml of a 20% KNO3 solution.
Explanation:
In the given question it is mentioned that
S1=50%
V2=250ml
S2= 20%
We all know that
V1S1=V2S2
∴V1= V2×S2÷S1
∴V1= V2S2×1/S1
∴V1= 250×20÷50
∴V1= 100ml
Answer:
The gravitational pull of a black hole is so strong that nothing, not even light, can escape once it gets too close. ... Moving at close to the speed of light, these particles ricochet off the event horizon and get hurled outward along the black hole's axis of rotation
(True)
A = Z + n
A = 12 + 10
A = 22
Answer C
hope this helps!