16
MCQ (Single Correct Answer)
Which of the following compounds is used for water softening?
A
$\mathrm{Ca}_3\left(\mathrm{PO}_4\right)_2$
B
$\mathrm{Na}_3 \mathrm{PO}_4$
C
$\mathrm{Na}_6 \mathrm{P}_6 \mathrm{O}_{18}$
D
$\mathrm{Na}_2 \mathrm{HPO}_4$
17
MCQ (Single Correct Answer)
Elements of which of the following group(s) of periodic table do not form hydrides?
A
Groups 7, 8, 9
B
Group 13
C
Groups $15,16,17$
D
Group 14
18
MCQ (Single Correct Answer)
Only one element of ........... forms hydride.
A
group 6
B
group 7
C
group 8
D
group 9
19
MCQ (Multiple Correct Answer)
Which of the following statements are not true for hydrogen?
A
It exists as diatomic molecule
B
It has one electron in the outermost shell
C
It can lose an electron to form a cation which can freely exist
D
It forms a large number of ionic compounds by losing an electron
20
MCQ (Multiple Correct Answer)
Dihydrogen can be prepared on commercial scale by different methods. In its preparation by the action of steam on hydrocarbons, a mixture of CO and $\mathrm{H}_2$ gas is formed. It is known as ........... .
A
water gas
B
syn gas
C
producer gas
D
industrial gas