А) N a 2 C O 3 Na_{2}CO_{3} N a 2 C O 3 — 2) H B r , C a ( N O 3 ) 2 , H N O 3 HBr,\ Ca(NO_{3})_{2},\ HNO_{3} H B r , C a ( N O 3 ) 2 , H N O 3
N a 2 C O 3 + 2 H B r = 2 N a B r + H 2 O + C O 2 ↑ Na_{2}CO_{3} + 2HBr = 2NaBr + H_{2}O + CO_{2}\uparrow N a 2 C O 3 + 2 H B r = 2 N a B r + H 2 O + C O 2 ↑
N a 2 C O 3 + C a ( N O 3 ) 2 = C a C O 3 ↓ + 2 N a N O 3 Na_{2}CO_{3} + Ca(NO_{3})_{2} = CaCO_{3}\downarrow + 2NaNO_{3} N a 2 C O 3 + C a ( N O 3 ) 2 = C a C O 3 ↓ + 2 N a N O 3
N a 2 C O 3 + 2 H N O 3 = 2 N a N O 3 + H 2 O + C O 2 ↑ Na_{2}CO_{3} + 2HNO_{3} = 2NaNO_{3} + H_{2}O + CO_{2}\uparrow N a 2 C O 3 + 2 H N O 3 = 2 N a N O 3 + H 2 O + C O 2 ↑
Б) F e Fe F e — 4) S , C u S O 4 , H C l S,\ CuSO_{4},\ HCl S , C u S O 4 , H C l
F e + S → t F e S Fe + S \overset{t}{\rightarrow} FeS F e + S → t F e S
F e + C u S O 4 = F e S O 4 + C u ↓ Fe + CuSO_{4} = FeSO_{4} + Cu\downarrow F e + C u S O 4 = F e S O 4 + C u ↓
F e + 2 H C l = F e C l 2 + H 2 ↑ Fe + 2HCl = FeCl_{2} + H_{2}\uparrow F e + 2 H C l = F e C l 2 + H 2 ↑
В) H 3 P O 4 H_{3}PO_{4} H 3 P O 4 — 5) C a , N H 3 , Z n ( O H ) 2 Ca,\ NH_{3},\ Zn(OH)_{2} C a , N H 3 , Z n ( O H ) 2
2 H 3 P O 4 + 3 C a = C a 3 ( P O 4 ) 2 ↓ + 3 H 2 ↑ 2H_{3}PO_{4} + 3Ca = Ca_{3}(PO_{4})_{2}\downarrow + 3H_{2}\uparrow 2 H 3 P O 4 + 3 C a = C a 3 ( P O 4 ) 2 ↓ + 3 H 2 ↑
H 3 P O 4 + 3 N H 3 = ( N H 4 ) 3 P O 4 H_{3}PO_{4} + 3NH_{3} = (NH_{4})_{3}PO_{4} H 3 P O 4 + 3 N H 3 = ( N H 4 ) 3 P O 4
2 H 3 P O 4 + 3 Z n ( O H ) 2 = Z n 3 ( P O 4 ) 2 ↓ + 6 H 2 O 2H_{3}PO_{4} + 3Zn(OH)_{2} = Zn_{3}(PO_{4})_{2}\downarrow + 6H_{2}O 2 H 3 P O 4 + 3 Z n ( O H ) 2 = Z n 3 ( P O 4 ) 2 ↓ + 6 H 2 O
Г) C r 2 O 3 Cr_{2}O_{3} C r 2 O 3 — 1) H N O 3 , K O H , A l HNO_{3},\ KOH,\ Al H N O 3 , K O H , A l
C r 2 O 3 + 6 H N O 3 = 2 C r ( N O 3 ) 3 + 3 H 2 O Cr_{2}O_{3} + 6HNO_{3} = 2Cr(NO_{3})_{3} + 3H_{2}O C r 2 O 3 + 6 H N O 3 = 2 C r ( N O 3 ) 3 + 3 H 2 O
C r 2 O 3 + 2 K O H → t 2 K C r O 2 + H 2 O Cr_{2}O_{3} + 2KOH \overset{t}{\rightarrow} 2KCrO_{2} + H_{2}O C r 2 O 3 + 2 K O H → t 2 K C r O 2 + H 2 O
C r 2 O 3 + 2 A l → t A l 2 O 3 + 2 C r Cr_{2}O_{3} + 2Al \overset{t}{\rightarrow} Al_{2}O_{3} + 2Cr C r 2 O 3 + 2 A l → t A l 2 O 3 + 2 C r
Почему не подходят остальные наборы:
N a 2 C O 3 + A l ( O H ) 3 = Na_{2}CO_{3} + Al(OH)_{3}\ \cancel{=} N a 2 C O 3 + A l ( O H ) 3 = N a 2 C O 3 + L i 3 P O 4 = Na_{2}CO_{3} + Li_{3}PO_{4}\ \cancel{=} N a 2 C O 3 + L i 3 P O 4 =
F e + K O H = Fe + KOH\ \cancel{=} F e + K O H = F e + N H 3 = Fe + NH_{3}\ \cancel{=} F e + N H 3 =
H 3 P O 4 + S O 2 = H_{3}PO_{4} + SO_{2}\ \cancel{=} H 3 P O 4 + S O 2 = H 3 P O 4 + C a ( N O 3 ) 2 = H_{3}PO_{4} + Ca(NO_{3})_{2}\ \cancel{=} H 3 P O 4 + C a ( N O 3 ) 2 =
C r 2 O 3 + N H 3 = Cr_{2}O_{3} + NH_{3}\ \cancel{=} C r 2 O 3 + N H 3 = C r 2 O 3 + H C l = Cr_{2}O_{3} + HCl\ \cancel{=} C r 2 O 3 + H C l = C r 2 O 3 Cr_{2}O_{3} C r 2 O 3
Ответ: 2451