Which one of the following statements is true for all the alkali metals?

• They react with halogens to give the halides MX

• Their nitrates decompose on heating to give NO₂ and O₂

• Their carbonates decompose on heating to give CO₂ and the metal oxide

• They react with oxygen to give mainly the oxide MO2

Which pair of the following chlorides do not impart colour to the flame?

• BeCl₂ and SrCl₂

• BeCl₂ and MgCl₂

• CaCl₂ and BaCl₂

• BaCl₂ and SrCl₂

The carbonate that will not decompose on heating is

• Na₂CO₃

• CaCO₃

• BaCO₃

• SrCO₃

Which one of the following on hydrolysis, gives the corresponding metallic hydroxide, H₂O₂ and O₂?

• Li₂O

• Na₂O₂

• NaO₂

• Na₂O

The effective component, of bleaching powder............is the of calcium :

• Cl^-

• OCl^-

• O^2-

• O₂Cl^-

Be and Al exhibit diagonal relationship. Which of the following statements about them is/ are not true?

I. Both react with HCl to liberate H2

II. They are made passive by HNO₃

Ill. Their carbides give acetylene on treatment with water

IV. Their oxides are amphoteric

• III only

• III and IV

• I and III

• I only

The metal that produces red-violet colour in the non-luminous flame is

• Ba

• Ag

• Rb

• Pb

Sodium peroxide which is a yellow solid, when exposed to air becomes white due to the formation of

• H₂O₂

• NaOH and Na₂CO₃

• Na₂O

• NaOH and H₂O₂

Thomas slag is referred to as :

• calcium silicate

• calcium phosphate

• barium phosphate

• strontium silicate

Alkali metals have high oxidation potential and hence, they behave as :

• oxidizing agents

• Lewis bases

• reducing agents

• electrolytes