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Lead perchlorate trihydrate is produced by the reaction of lead(II) oxide, lead carbonate, or lead nitrate by perchloric acid: . Pb(NO 3) 2 + HClO 4 → Pb(ClO 4) 2 + HNO 3. The excess perchloric acid was removed by first heating the solution to 125 °C, then heating it under moist air at 160 °C to remove the perchloric acid by converting the acid to the dihydrate.
The base was located on Highway 1 approximately 8 km northwest of Quảng Trị and 8 km southeast of Đông Hà beside the Thạch Hãn River. [1]Following a series of artillery and rocket attacks on Đông Hà Combat Base, the Marines' major logistics and aviation support base in northern Quảng Trị Province, throughout the year, the Marines decided that Đông Hà was too vulnerable to ...
The postal code system of Vietnam has officially been changed from 6 digits to 5 digits. Each country has its own separate postal code or zip code system. The postal code of Vietnam is composed of 5 digits, with the following meanings: [2] [3] The first digit determines the area code.
According to documents, at the beginning of emperor Gia Long's reign, Quang Tri citadel was constructed in the Tiền Kiên ward. In 1809, wanting to secure the North of the then capital Phú Xuân, the emperor ordered to move the citadel to Thạch Hãn commune (i.e. the present location), which he deemed a position with strategic advantages in terms of politics, economy, and military.
By 11:00 on 2 April the ARVN 20th Tank Regiment moved forward to Đông Hà to support the 3rd Marine Battalion and 25th Marine Brigade in and around the town and defend the crucial road and rail bridges across the Cua Viet River. [8]: 50–2 Marine ANGLICO units called in naval gunfire to hit PAVN forces near the bridges on the north bank of ...
The Second Battle of Quang Tri (Vietnamese: Trận Thành cổ Quảng Trị; also called Operation Lam Sơn 72) began on 28 June 1972 and lasted 81 days until 16 September 1972, when South Vietnam's Republic of Vietnam Military Forces defeated the North Vietnamese People's Army of Vietnam (PAVN) at the ancient citadel of Quảng Trị (Vietnamese: Thành cổ Quảng Trị) and recaptured ...
It is then converted to the ammonium salt (NH 4) 2 PbCl 6 by adding ammonium chloride (NH 4 Cl). Finally, the solution is treated with concentrated sulfuric acid H 2 SO 4, to separate out lead tetrachloride. This series of reactions is conducted at 0 °C. The following equations illustrate the reaction: PbCl 2 + 2HCl + Cl 2 → H 2 PbCl 6
Following the conclusion of the Tri Thien and Tin-Ngai Campaigns, the PAVN High Command ordered General Lê Trọng Tấn to journey south from Hanoi and personally take charge of the Da Nang Campaign. Subsequently, on March 25, the North Vietnamese came up with a plan to attack Da Nang from four directions: