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(A) $I$. In the borax bead test, cobalt oxide reacts with $B_2O_3$ to form cobalt metaborate, $Co(BO_2)_2$, which is blue in color. This statement is

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$I$ & $II$

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(A) $I$. In the borax bead test, cobalt oxide reacts with $B_2O_3$ to form cobalt metaborate, $Co(BO_2)_2$, which is blue in color. This statement is correct.$II$. Diborane $(B_2H_6)$ is prepared by the reaction of sodium borohydride $(NaBH_4)$ with iodine $(I_2)$: $2NaBH_4 + I_2 \rightarrow B_2H_6 + 2NaI + H_2$. This statement is correct.$III$. In diborane $(B_2H_6)$, boron is more electropositive than hydrogen, so the oxidation state of hydrogen is $-1$. This statement is incorrect.$IV$. Boric acid $(H_3BO_3)$ is a weak monobasic Lewis acid, not a tribasic acid, as it accepts $OH^-$ ions from water. This statement is incorrect.Therefore, statements $I$ and $II$ are correct.

List-$I$ (Group $13$ element)	List-$II$ (Metallic radius,$pm$)
$A$. $Al$	$I$. $135$
$B$. $Ga$	$II$. $143$
$C$. $In$	$III$. $170$
$D$. $Tl$	$IV$. $167$

The correct statements about the compounds of boron are:
$I$. In borax bead test, the colour of cobalt metaborate is blue.
$II$. Diborane is prepared by the oxidation of sodium borohydride with iodine.
$III$. In diborane, the oxidation state of hydrogen is $+1$.
$IV$. Boric acid is a tribasic acid.

Similar Questions

Match the following:
List-$I$ (Group $13$ element) List-$II$ (Metallic radius,$pm$)
$A$. $Al$ $I$. $135$
$B$. $Ga$ $II$. $143$
$C$. $In$ $III$. $170$
$D$. $Tl$ $IV$. $167$

The correct answer is:

Chemically,borax is:

Which one of the following statements is correct?

Diborane reacts with ammonia to form $X$, which on heating gives $H_2$ and borazine. $X$ is

Which of the following is added to borax to obtain boric acid?

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The correct statements about the compounds of boron are:$I$. In borax bead test, the colour of cobalt metaborate is blue.$II$. Diborane is prepared by the oxidation of sodium borohydride with iodine.$III$. In diborane, the oxidation state of hydrogen is $+1$.$IV$. Boric acid is a tribasic acid.