Problem 77
The reducing agent in thermite process is (a) \(\mathrm{Mg}\) (b) \(\mathrm{BaO}_{2}\) (c) \(\mathrm{Al}\) (d) \(\mathrm{MnO}_{2}\)
Problem 79
The alum used for purifying water is (a) potash alum (b) chrome alum (c) ferric alum (d) ammonium alum
Problem 81
Which of the following alloy is used for making magnets for hearing aids? (a) invar (b) german silver (c) monel metal (d) alnico
Problem 82
Emery consists of impure (a) iron (b) corundum (c) carborundum (d) graphite
Problem 83
The molecular formula of potash alum is (a) \(\mathrm{K}_{2} \mathrm{Al}_{2} \mathrm{~S}_{2} \mathrm{H}_{48} \mathrm{O}_{39}\) (b) \(\mathrm{KAl}_{2} \mathrm{~S}_{2} \mathrm{H}_{48} \mathrm{O}_{40}\) (c) \(\mathrm{K}_{2} \mathrm{AlS}_{2} \mathrm{H}_{48} \mathrm{O}_{40}\) (d) \(\mathrm{K}_{2} \mathrm{Al}_{2} \mathrm{~S}_{2} \mathrm{H}_{48} \mathrm{O}_{40}\)
Problem 84
Which of the following is not correct? (a) Al reacts with \(\mathrm{NaOH}\) and liberates \(\mathrm{H}_{2}\) (b) \(\mathrm{AlCl}_{3}\) is a Lewis acid (c) Al is used in the manufacture of electrical cables (d) \(\mathrm{NaOH}\) is used during Halls process of purification of bauxite
Problem 85
Which of the following is known as pseudo alum? (a) \(\mathrm{K}_{2} \mathrm{SO}_{4} \cdot \mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3} \cdot 24 \mathrm{H}_{2} \mathrm{O}\) (b) \(\mathrm{KCr}\left(\mathrm{SO}_{4}\right)_{2}, 12 \mathrm{H}_{2} \mathrm{O}\) (c) \(\mathrm{KMn}\left(\mathrm{SO}_{4}\right)_{2} \cdot 12 \mathrm{H}_{2} \mathrm{O}\) (d) \(\mathrm{NH}_{4} \mathrm{Fe}\left(\mathrm{SO}_{4}\right)_{2} \cdot 12 \mathrm{H}_{2} \mathrm{O}\)
Problem 86
Which of the following compound transforms baking soda into baking powder? (a) \(\mathrm{KHCO}_{3}\) (b) \(\mathrm{NaHCO}_{3}\) (c) \(\mathrm{KHC}_{4} \mathrm{H}_{4} \mathrm{O}_{6}\) (d) \(\mathrm{KCl}\)
Problem 87
Sodium hydroxide being hygroscopic absorbs moisture when exposed to the atmosphere. A student placed a pellet of \(\mathrm{NaOH}\) on a watch glass. A few days later, he noticed that the pellet was covered with a white solid. Identify this white solid? (a) Na metal (b) \(\mathrm{Na}_{2} \mathrm{SO}_{3}\) (c) \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) (d) \(\mathrm{Na}_{2} \mathrm{~S}\)
Problem 88
In the reaction: \(\mathrm{K}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]+\mathrm{K}_{2} \mathrm{CO}_{3} \longrightarrow\) the product formed is (a) \(\mathrm{FeCO}_{3}\) (b) \(\mathrm{KCN}\) (c) \(\mathrm{KFeCO}_{3}\) (d) \(\mathrm{K}_{3}\left[\mathrm{Fe}(\mathrm{CN})_{4}\right]\)
