HSC, Admission ও BCS এর সেরা প্রস্তুতি

প্রশ্ন ৮·সময় ২ ঘণ্টা ৩৫ মিনিট

1. (i) $\mathrm{Fe}^{2+}+\mathrm{MnO}_{4}+\mathrm{H}^{+} \longrightarrow \mathrm{Fe}^{3+}+\mathrm{Mn}^{2+}+\mathrm{H}_{2} \mathrm{O}$

(ii) $\mathrm{I}_{2}+\mathrm{S}_{2} \mathrm{O}_{3}^{2} \longrightarrow \mathrm{S}_{4} \mathrm{O}_{6}^{2}+\mathrm{I}^{-}$

(iii) $\mathrm{HCOOH}+\mathrm{Na}_{2} \mathrm{CO}_{3} \longrightarrow \mathrm{HCOONa}+\mathrm{H}_{2} \mathrm{O}+\mathrm{CO}_{2}$

DB 19

Industry

Components

No-1

Air, natural gas

No-2

Leather, lime,

$Na_{2\ }Cr_{2\ }O-7,\ H_2\ SO_4$

No-3

Scrap ship

DB 19

DB 19

Solution- 1	$15\ mL\ 0.02M\ H_2C_2O_4$
Solution- 2	5 mL 10% NaOH

Indicator	Range of pH change
A	3.1-4.4
A	8.3-10.0

DB 19

DB 19

Chemistry 2nd Paper CQ-Dhaka Board-2019