Which ion forms a hydroxide highly soluble in water?
(a) Ni2+
(b) K+
(c) Zn2+
(d) Al3+
(b) Alkali metal hydroxides are highly soluble in water.
Difficulty Level:
A colourless salt gives violet colour to Bunsen flame and also turns moistured litmus paper blue. It Is:
(a) Na2CO3
(b) KNO3
(c) K2CO3
(d) Cu(OH)2
(c) Violet colour to flame is characteristic of potassium. Also aqueous solution of K2CO3 is alkaline.
Difficulty Level:
Strongest reducing agent among the following is:
(a) K
(b) Na
(c) Al
(d) Mg
(a) Alkali metals are strongest reducing agents. Also, their reducing power increases down the group.
Difficulty Level:
When crystal of caustic soda is exposed to air, a liquid layer is deposited because:
(a) crystal melts
(b) crystal loses water
(c) crystal absorbs moisture and CO2
(d) crystal sublimes
(c) NaOH absorbs moisture and CO2 from air to form Na2CO3,
2
Difficulty Level:
Which one of the following is formed on dissolving I2 in aqueous solution of KI ?
(a) KIO4
(b) KIO
(c) KI3
(d) KIO3
(C)
Difficulty Level:
Brine is chemically:
(a) conc. solution of Na2CO3
(b) conc. solution of Na2SO4
(c) conc. solution of NaCl
(d) conc. solution of alum
(c) It is a fact.
Difficulty Level:
Sodium reacts with water less vigorously than potassium because:
(a) it has higher atomic weight
(b) it is less electropositive
(c) it is more electronegative
(d) it is metal
(b) The reactivity of alkali metals increases down the group.
Difficulty Level:
Which property increases in magnitude as the atomic number of alkali metals increases ?
(a) Electronegativity
(b) First ionisation energy
(c) Ionic radius
(d) Melting point
(c) Ionic radius increases down the group.
Difficulty Level:
Common table salt becomes moist and does not pour easily in rainy season because:
(a) it contains magnesium chloride
(b) it contains magnesium carbonate
(c) it melts slightly in rainy season
(d) sodium chloride is hygroscopic
(a) MgCl2 is hygroscopic
Difficulty Level:
a mixture of Al(OH)3 and Fe(OH)3 can be seperated easily by treating it with:
(a) HCl
(b) NH4OH
(c) HNO3
(d) NaOH
(d) Al(OH)3 is soluble in NaOH(aq) whereas Fe(OH)3 is insoluble.
Difficulty Level: