16
MCQ (Single Correct Answer)
Which of the following elements does not form hydride by direct heating with dihydrogen?
A
Be
B
Mg
C
Sr
D
Ba
17
MCQ (Single Correct Answer)
The formula of soda ash is
A
$\mathrm{Na}_2 \mathrm{CO}_3 \cdot 10 \mathrm{H}_2 \mathrm{O}$
B
$\mathrm{Na}_2 \mathrm{CO}_3 \cdot 2 \mathrm{H}_2 \mathrm{O}$
C
$\mathrm{Na}_2 \mathrm{CO}_3 \cdot \mathrm{H}_2 \mathrm{O}$
D
$\mathrm{Na}_2 \mathrm{CO}_3$
18
MCQ (Single Correct Answer)
A substance which gives brick red flame and breaks down on heating to give oxygen and a brown gas is
A
magnesium nitrate
B
calcium nitrate
C
barium nitrate
D
strontium nitrate
19
MCQ (Single Correct Answer)
Which of the following statements is true about $\mathrm{Ca}(\mathrm{OH})_2$ ?
A
It is used in the preparation of bleaching powder
B
It is a light blue solid
C
It does not possess disinfectant property
D
It is used in the manufacture of cement
20
MCQ (Single Correct Answer)
A chemical $A$ is used for the preparation of washing soda to recover ammonia. When $\mathrm{CO}_2$ is bubbled through an aqueous solution of A , the solution turns milky. It is used in white washing due to disinfectant nature. What is the chemical formula of $A$ ?
A
$\mathrm{Ca}\left(\mathrm{HCO}_3\right)_2$
B
CaO
C
$\mathrm{Ca}(\mathrm{OH})_2$
D
$\mathrm{CaCO}_3$